United States                            EPA/600/R-05/040
      Environmental Protection Agency             Revised July 2010
STORM WATER MANAGEMENT MODEL

               USER'S MANUAL

                  Version 5.0
                         By
                    Lewis A. Rossman
           Water Supply and Water Resources Division
          National Risk Management Research Laboratory
                  Cincinnati, OH 45268
     NATIONAL RISK MANAGEMENT RESEARCH LABORATORY
          OFFICE OF RESEARCH AND DEVELOPMENT
         U.S. ENVIRONMENTAL PROTECTION AGENCY
                  CINCINNATI, OH 45268

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

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

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                                   FOREWORD

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

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

Water quality impairment due to runoff  from  urban and developing areas continues to be a major
threat to the ecological  health of our nation's waterways. The  EPA  Stormwater Management
Model  is  a  computer program that can  assess the impacts of such runoff and evaluate the
effectiveness of mitigation  strategies.  The  modernized  and updated  version  of  the model
described in this document will make it a more accessible and valuable tool for researchers and
practitioners engaged in water resources  and water quality planning and management.

                                                        Sally C. Gutierrez, Acting Director
                                            National Risk Management Research Laboratory
                                           MI

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                          ACKNOWLEDGEMENTS
The development of SWMM 5 was pursued under a Cooperative Research and Development
Agreement between the Water Supply and Water Resources Division of the U.S. Environmental
Protection Agency and the consulting engineering firm of Camp Dresser & McKee Inc. The
project team consisted of the following individuals:

                 US EPA                         COM
                 Lewis Rossman                   Robert Dickinson
                 Trent Schade                     Carl Chan
                 Daniel Sullivan (retired)           Edward Burgess

The team would like to acknowledge the assistance  provided by Wayne Huber (Oregon State
University), Dennis Lai (US EPA), and Michael Gregory (COM). We also want to acknowledge
the contributions made by the  following individuals to previous versions of SWMM that we drew
heavily  upon in this  new version:  John Aldrich,  Douglas Ammon,  Carl W.  Chen, Brett
Cunningham,  Robert Dickinson, James Heaney, Wayne Huber, Miguel  Medina, Russell Mein,
Charles Moore,  Stephan Nix, Alan Peltz, Don Polmann, Larry Roesner, Charles Rowney, and
Robert Shubinsky. Finally, we wish to thank Wayne  Huber, Thomas Barnwell  (US EPA),
Richard Field (US EPA), Harry Torno  (US EPA retired) and William James (University  of
Guelph) for their continuing efforts to support and maintain  the program over the past several
decades.
                                          IV

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                                  CONTENTS





CHAPTER 1 - INTRODUCTION	1




1.1     What is SWMM	1




1.2     Modeling Capabilities	1




1.3     Typical Applications of SWMM	2




1.4     Installing EPA SWMM	3




1.5     Steps in Using SWMM	3




1.6     About This Manual	4





CHAPTER 2 - QUICK START TUTORIAL	7




2.1     Example Study Area	7




2.2     Project Setup	7




2.3     Drawing Objects	10




2.4     Setting Object Properties	12




2.5     Running a Simulation	17




2.6     Simulating Water Quality	26




2.7     Running a Continuous Simulation	30





CHAPTER 3 - SWMM'S CONCEPTUAL MODEL	33




3.1     Introduction	33




3.2     Visual Objects	33




3.3     Non-Visual Objects	43




3.4     Computational Methods	55





CHAPTER 4 - SWMM'S MAIN WINDOW	63




4.1     Overview	63

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4.2     Main Menu	64




4.3     Toolbars	67




4.4     Status Bar	69




4.5     Study Area Map	70




4.6     Data Browser	71




4.7     Map Browser	71




4.8     Property Editor	73




4.9     Setting Program Preferences	74





CHAPTER 5-WORKING WITH PROJECTS	77




5.1     Creating a New Project	77




5.2     Opening an Existing Project	77




5.3     Saving a Project	77




5.4     Setting Project Defaults	78




5.5     Measurement Units	80




5.6     Link Offset Conventions	81




5.7     Calibration Data	81




5.8     Viewing All Project Data	83





CHAPTER 6 - WORKING WITH OBJECTS	85




6.1     Types of Objects	85




6.2     Adding Objects	85




6.3     Selecting and Moving Objects	88




6.4     Editing Objects	88




6.5     Converting an Object	89




6.6     Copying and Pasting Objects	89




6.7     Shaping and Reversing Links	90




6.8     Shaping a Subcatchment	90
                                         VI

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6.9     Deleting an Object	91




6.10    Editing or Deleting a Group of Objects	91





CHAPTER 7 - WORKING WITH THE MAP	93




7.1     Selecting a Map Theme	93




7.2     Setting the Map's Dimensions	93




7.3     Utilizing a Backdrop Image	94




7.4     Measuring Distances	97




7.5     Zooming the Map	98




7.6     Panning the Map	98




7.7     Viewing at Full Extent	98




7.8     Finding an Object	99




7.9     Submitting a Map Query	99




7.10    Using the Map Legends	100




7.11    Using the Overview Map	101




7.12    Setting Map Display Options	102




7.13    Exporting the Map	106





CHAPTER 8 - RUNNING A  SIMULATION	109




8.1     Setting Simulation Options	109




8.2     Setting Reporting Options	115




8.3     Starting a Simulation	116




8.4     Troubleshooting Results	116





CHAPTER 9 - VIEWING  RESULTS	121




9.1     Viewing a Status Report	121




9.2     Variables That Can Be Viewed	124




9.3     Viewing Results on the Map	125




9.4     Viewing Results with  a Graph	125






                                        vii

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9.5     Customizing a Graph's Appearance	130




9.6     Viewing Results with a Table	134




9.7     Viewing a Statistics Report	136





CHAPTER 10 - PRINTING AND COPYING	141




10.1    Selecting a Printer	141




10.2    Setting the Page Format	142




10.3    Print Preview	143




10.4    Printing the Current View	143




10.5    Copying to the Clipboard or to a File	143





CHAPTER 11 - FILES USED BY SWMM	145




11.1    Project Files	145




11.2    Report and Output Files	145




11.3    Rainfall Files	146




11.4    Climate Files	146




11.5    Calibration Files	147




11.6    Time Series Files	148




11.7    Interface Files	149





CHAPTER 12 - USING ADD-IN TOOLS	153




12.1    What Are Add-In Tools	153




12.2    Configuring Add-In Tools	154





APPENDIX A-USEFUL TABLES	159




A.I    Units of Measurement	159




A.2    Soil Characteristics	160




A.3    NRCS Hydrologic Soil Group Definitions	161




A.4    SCS Curve Numbers	162
                                        VIM

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A.5     Depression Storage	163




A.6     Manning's n- Overland Flow	163




A.7     Manning's n- Closed Conduits	164




A.8     Manning's n- Open Channels	165




A. 9     Water Quality Characteristics of Urban Runoff	165




A. 10   Culvert Code Numbers	166




A.11   Culvert Entrance Loss Coefficients	168





APPENDIX B -VISUAL OBJECT PROPERTIES	169




B.I     Rain Gage Properties	169




B.2     Subcatchment Properties	170




B.3     Junction Properties	172




B.4     Outfall Properties	173




B.5     Flow Divider Properties	174




B.6     Storage Unit Properties	175




B.7     Conduit Properties	176




B.8     Pump Properties	177




B.9     Orifice Properties	177




B.10   Weir Properties	178




B.ll   Outlet Properties	179




B.12   Map Label Properties	180





APPENDIX C - SPECIALIZED PROPERTY EDITORS	181




C.I     Aquifer Editor	181




C.2     Climatology Editor	182




C.3     Control Rules Editor	190




C.4     Cross-Section Editor	194




C.5     Curve Editor	195
                                         IX

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C.6     Groundwater Flow Editor	196




C.7     Infiltration Editor	198




C.8     Inflows Editor	201




C.9     Initial Buildup Editor	205




C.10   Land Use Editor	205




C.ll   Land Use Assignment Editor	210




C.12   LID Control Editor	211




C.13   LID Group Editor	215




C.14   LID Usage Editor	216




C.15   Pollutant Editor	218




C16.   Snow Pack Editor	219




C.17   Time Pattern Editor	223




C.18   Time Series Editor	224




C.19   Title/Notes Editor	226




C.20   Transect Editor	227




C.21   Treatment Editor	228




C.22   Unit Hydrograph Editor	229





APPENDIX D-COMMAND LINE SWMM	231





APPENDIX E-ERROR AND WARNING MESSAGES	277

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CHAPTER 1 - INTRODUCTION
1.1    What is SWMM

The EPA Storm Water Management Model (SWMM) is  a dynamic rainfall-runoff simulation
model used for single event or long-term (continuous) simulation of runoff quantity and quality
from  primarily urban  areas.  The  runoff component  of SWMM operates on a  collection  of
subcatchment areas that receive precipitation and generate runoff and pollutant loads. The routing
portion of SWMM transports this runoff through a system of pipes, channels, storage/treatment
devices, pumps, and regulators. SWMM tracks the quantity and quality of runoff generated within
each subcatchment,  and the flow rate, flow depth, and quality  of water in each pipe and channel
during a simulation period comprised of multiple time steps.

SWMM was  first developed in  19711 and has undergone several major upgrades since then2. It
continues to be widely used throughout the world for planning, analysis and design related to
storm water runoff, combined sewers, sanitary sewers, and other drainage systems in urban areas,
with many applications in non-urban areas as well.  The current edition, Version 5,  is  a complete
re-write of the previous release.  Running under Windows,  SWMM 5 provides  an  integrated
environment for editing study area input data, running hydrologic, hydraulic and  water quality
simulations,  and viewing the results in a variety of formats. These include  color-coded drainage
area and conveyance system  maps, time series graphs and tables, profile plots, and statistical
frequency analyses.

This latest re-write of SWMM was produced by the Water Supply and Water Resources Division
of the U.S. Environmental Protection Agency's National Risk Management Research Laboratory
with assistance from the consulting firm of CDM, Inc
1.2     Modeling Capabilities

SWMM accounts for various hydrologic processes that produce runoff from urban areas. These
include:
    •  time-varying rainfall
    •  evaporation of standing surface water
    •  snow accumulation and melting
    •  rainfall interception from depression storage
    •  infiltration of rainfall into unsaturated soil layers
    •  percolation of infiltrated water into groundwater layers
    •  interflow between groundwater and the drainage system
    •  nonlinear reservoir routing of overland flow
1 Metcalf & Eddy, Inc., University of Florida, Water Resources Engineers, Inc. "Storm Water Management
Model, Volume I - Final Report", 11024DOC07/71, Water Quality Office, Environmental Protection
Agency,  Washington, DC, July 1971.
2 Huber,  W. C. and Dickinson, R.E., "Storm Water Management Model, Version 4: User's Manual",
EPA/600/3-88/00la, Environmental Research Laboratory, U.S. Environmental Protection Agency, Athens,
GA, October 1992.

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    •  capture and retention of rainfall/runoff with various types of low impact development
       (LID) practices.

Spatial variability in all of these processes is achieved by dividing a study area into a collection of
smaller, homogeneous subcatchment  areas,  each containing its own fraction of pervious and
impervious sub-areas. Overland flow can be routed between sub-areas, between subcatchments,
or between entry points of a drainage system.

SWMM also contains a flexible  set of hydraulic modeling capabilities used to route runoff and
external inflows through the drainage system network of pipes, channels, storage/treatment units
and diversion structures. These include the ability to:
    •  handle networks of unlimited size
    •  use a wide variety of standard closed and open conduit shapes as well as natural channels
    •  model special elements such as storage/treatment units, flow dividers, pumps, weirs, and
       orifices
    •  apply external flows and water quality inputs from surface runoff, groundwater interflow,
       rainfall-dependent infiltration/inflow, dry weather sanitary flow, and user-defined inflows
    •  utilize either kinematic wave or full dynamic wave flow routing methods
    •  model various flow regimes, such as backwater, surcharging, reverse flow, and surface
       ponding
    •  apply user-defined dynamic control rules to simulate the operation of pumps, orifice
       openings, and weir crest levels.

In addition to modeling the  generation and transport of runoff flows, SWMM can also estimate
the production  of pollutant  loads associated  with  this  runoff. The  following processes can be
modeled for any number of user-defined water quality constituents:
    •  dry-weather pollutant buildup over different land uses
    •  pollutant washoff from specific land uses during storm events
    •  direct contribution of rainfall deposition
    •  reduction in dry-weather buildup due to street cleaning
    •  reduction in washoff load due to BMPs
    •  entry of dry weather sanitary flows and user-specified external inflows at any point in the
       drainage system
    •  routing of water quality constituents through the drainage system
    •  reduction in constituent concentration through treatment in storage units or by natural
       processes in pipes and channels.
1.3     Typical Applications of SWMM

Since its  inception, SWMM  has  been used in thousands of sewer and stormwater studies
throughout the world. Typical applications include:
    •   design and sizing of drainage system components for flood control
    •   sizing of detention facilities and their appurtenances for flood control and water quality
        protection
    •   flood plain mapping of natural channel systems
    •   designing control strategies for minimizing combined sewer overflows
    •   evaluating the impact of inflow and infiltration on sanitary sewer overflows
    •   generating non-point source pollutant loadings for waste load allocation studies
    •   evaluating the effectiveness of BMPs for reducing wet weather pollutant loadings.

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1.4    Installing EPA SWMM

EPA SWMM  Version 5  is designed to run under the Windows  98/NT/ME/2000/XP/Vista/7
operating system of an IBM/Intel-compatible personal computer. It is distributed as a single file,
epaswmm5_setup.exe, which contains a self-extracting setup program. To install EPA SWMM:
    1.  Select Run from the Windows Start menu.
    2.  Enter the full path and name of the epaswmm5_setup.exe file or click the Browse button
       to locate it on your computer.
    3.  Click the OK button type to begin the setup process.

The setup program will ask you to choose a folder (directory) where the SWMM program files
will be placed. The  default folder  is c:\Program Files\EPA SWMM 5.0. After the files are
installed your  Start Menu  will  have a new item named EPA SWMM 5.0. To launch SWMM,
simply select this item off of the Start Menu, and then select EPA SWMM 5.0 from the submenu
that  appears.  (The  name of  the  executable  file that runs  SWMM  under  Windows  is
epaswmm5.exe.)

Under Windows 2000, XP, Vista and 7, a user's personal settings for running SWMM are stored
in a folder named EPASWMM under the user's Application Data directory. If you need to save
these settings to a different location, you can install a shortcut to SWMM 5 on the desktop whose
target entry includes  the name  of the SWMM  5  executable followed by /s , where
 is the name  of the folder where the personal settings will be stored. An example
might be:

    "c: [Program Files \EPA SWMM 5.0 \epaswmm5. exe " /s  "My Folders \SWMM5 \".

To remove EPA SWMM from your computer, do the following:

    l.  Select Settings from the Windows Start menu.
    2.  Select Control Panel from the Settings menu.
    3.  Double-click on the Add/Remove Programs item.
    4.  Select EPA SWMM 5.0 from the list of programs that appears.
    5.  Click the Add/Remove button.
1.5    Steps in Using SWMM

One typically carries out the following steps when using SWMM to model stormwater runoff
over a study area:
    l.  Specify a default set of options and object properties to use (see Section 5.4).
    2.  Draw a network representation of the physical components of the study area (see Section
       6.2).
    3.  Edit the properties of the objects that make up the system (see Section 6.4).

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    4.  Select a set of analysis options (see Section 8.1).
    5.  Run a simulation (see Section 8.2).
    6.  View the results of the simulation (see Chapter 9).

Alternatively, a modeler may convert an input file from an older version of EPA SWMM instead
of developing a new model as in Steps 1 through 4.
1.6    About This Manual

Chapter 2 presents a short tutorial to help get started using EPA SWMM. It shows how to add
objects to a SWMM project, how to edit the properties of these objects, how to run a single event
simulation  for both hydrology and  water  quality, and how  to  run  a long-term continuous
simulation.

Chapter 3 provides background material on how SWMM models stormwater runoff within a
drainage  area. It discusses the behavior of the physical components that comprise a stormwater
drainage  area and collection system  as well as how additional modeling information, such as
rainfall quantity,  dry  weather sanitary inflows,  and operational control, are handled.  It  also
provides  an overview of how the numerical simulation of system hydrology, hydraulics and water
quality behavior is carried out.

Chapter 4 shows  how the EPA SWMM graphical user interface is organized. It describes the
functions of the various menu options and toolbar buttons, and how the three main windows - the
Study Area Map, the Browser panel, and the Property Editor—are used.

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

Chapter 6 describes how one goes about building a network model of a drainage system with
SWMM.  It shows how to create the various physical objects (subcatchment areas, drainage pipes
and channels, pumps, weirs, storage units, etc.) that make up a system, how to  edit the properties
of these  objects, and how  to describe the way that  externally  imposed inflows, boundary
conditions and operational controls change over time.

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

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

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

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

Chapter  11 describes  how  EPA SWMM can use  different types  of interface files to  make
simulations runs more efficient.

The manual also contains several appendixes:
Appendix A -   provides several useful tables of parameter values, including a table of units of
               expression for all design and computed parameters.
Appendix B -   lists the editable properties of all visual objects that can be displayed on the study
               area map and be selected for editing using point and click.
Appendix C -   describes the specialized editors available for setting  the properties of non-visual
               objects.
Appendix D -   provides instructions for running the command line version  of SWMM  and
               includes a detailed description of the format of a project file.
Appendix E -   lists all of the error messages and their meaning that SWMM can produce.

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(This page intentionally left blank.)

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CHAPTER 2 - QUICK START TUTORIAL
This chapter provides a tutorial on how  to use EPA SWMM. If you are not familiar with the
elements that comprise a drainage system,  and how these are represented in a SWMM model, you
might want to review the material in Chapter 3 first.
2.1    Example Study Area

In this tutorial we will model the drainage system serving a 12-acre residential area. The system
layout is  shown in  Figure 2-1 and consists of subcatchment areas3 SI through S3, storm sewer
conduits Cl through C4, and conduit junctions Jl through J4. The system discharges to a creek at
the point labeled Out I. We will first go through the steps of creating the objects shown in this
diagram on SWMM's study area map  and setting the various properties of these objects. Then we
will simulate the water quantity and quality response to a 3-inch, 6-hour rainfall event, as well as
a continuous, multi-year rainfall record.
                                                         Jl
                                                        T
Out1
V
C4
*
C3,
t
F
.14
h
m
\
C2
	 ^ 	
cs
x^
                            Figure 2-1. Example study area.
2.2    Project Setup

Our first task is to create a new SWMM project and make sure that certain default options are
selected. Using these defaults will simplify the data entry tasks later on.
    1.  Launch EPA SWMM if it is not already running and select File » New from the Main
       Menu bar to create a new project.
    2.  Select Project» Defaults to open the Project Defaults dialog.
3 A subcatchment is an area of land containing a mix of pervious and impervious surfaces whose
runoff drains to a common outlet point, which could be either a node of the drainage network or
another subcatchment.

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3.  On the ID Labels page of the dialog, set the ID Prefixes as shown in Figure 2-2. This will
    make SWMM automatically label new objects with consecutive numbers following the
    designated prefix.
                    Project Defaults
ID Labels Subcatchments Nodes/Links
Object
Rain Gages
Subcatchments
Junctions
Outfalls
Divideis
Storage Units
Conduits
Pumps
Regulators
ID Increment
ID Prefix
Gage
1i~
J
Out

C


1

                        ave as defaults for all new projects
                     I	or~i
        Cancel
               Figure 2-2. Default ID labeling for tutorial example.

    On the Subcatchments page of the dialog set the following default values:
       Area
       Width
       % Slope
       % Imperv.
       N-Imperv.
       N-Perv.
       Dstore-Imperv.
       Dstore-Perv
       %Zero-Imperv.
       Mil. Model
       - Method
       - Suction Head
       - Conductivity
       - Initial Deficit
4
400
0.5
50
0.01
0.10
0.05
0.05
25

Green-Ampt
3.5
0.5
0.26

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    5.  On the Nodes/Links page set the following default values:
       Node Invert           0
       Node Max. Depth      4
       Node Ponded Area     0
       Conduit Length        400
       Conduit Geometry     
           - Barrels          1
           - Shape           Circular
           -Max. Depth      1.0
       Conduit Roughness    0.01
       Flow Units            CFS
       Link Offsets          DEPTH
       Routing Model        Kinematic Wave
    6.  Click OK to  accept these choices and close the dialog. If you wanted to save these
       choices for all future new projects you could check the Save  box at the bottom of the
       form before accepting it.

Next we will set some map display options so that ID labels and symbols will be displayed as we
add objects to the study area map, and links will have direction arrows.
    l.  Select View » Map Options to bring up the Map Options dialog (see Figure 2-3).
    2.  Select the Subcatchments page, set the Fill Style to Diagonal and the Symbol Size to 5.
    3.  Then select the Nodes page and set the Node Size to 5.
    4.  Select the Annotation page and check off the boxes that will display ID labels for
       Subcatchments, Nodes, and Links. Leave the others un-checked.
    5.  Finally, select the Flow Arrows page, select the Filled arrow style, and set the arrow size
       to 7.
    6.  Click the OK button to accept these choices and close the dialog.

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                    Map Options
                      Subcatchrnents
                      Nodes

                      Links

                      Labels

                      Annotation

                      Symbols

                      Flow Arrows

                      Background
r
Fill Style
O Clear
O Solid
0 Diagonal
O Cross Hatch
    Symbol
    Size

    Outline
    Thickness
    0 Display link (o outlet
                              OK
                             Figure 2-3.  Map Options dialog.


Before placing objects on the map we should set its dimensions.
    1.  Select View » Dimensions to bring up the Map Dimensions dialog.
    2.  You can leave the dimensions at their default values for this example.

Finally, look in the  status bar at the bottom  of the main window and check that the Auto-Length
feature is off.
2.3     Drawing Objects

We are now ready to begin adding components to the  Study Area Map4. We will start with the
subcatchments.
    1.  Begin by clicking the LIU button on the Object Toolbar. (If the toolbar is not visible then
        select View » Toolbars » Object). Notice how the mouse cursor changes shape to a
        pencil.
4 Drawing objects on the map is just one way of creating a project. For large projects it might be
more convenient to first construct a SWMM project file external to the program. The project file
is a text file that describes each object in a specified format as described in Appendix D of this
manual. Data extracted from various sources, such as CAD drawings or GIS files, can be used to
create the project file.
                                            10

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    2.  Move the mouse to the map location where one of the corners of subcatchment SI lies
       and left-click the mouse.
    3.  Do the same for the next three corners and then right-click the mouse (or hit the Enter
       key) to close up the rectangle that represents subcatchment SI. You can press the Esc key
       if instead you wanted to cancel your partially drawn subcatchment and start over again.
       Don't worry if the  shape or position of the object isn't quite right. We will go back later
       and show how to fix this.
    4.  Repeat this process for subcatchments S2 and S35.
Observe how sequential ID labels are generated automatically as we add objects to the map.

Next we will add in the junction nodes and the outfall node that comprise part of the drainage
network.
    1.  To begin adding junctions, click the L^J button on the Object Toolbar
    2 .  Move the mouse to the position of junction Jl and left-click it. Do the same for junctions
       J2 through J4.

    3.  To add the outfall node, click the I    ' button on the Object Toolbar, move the mouse to
       the outfall's location on the map, and left-click. Note how the outfall was automatically
       given the name Out I.

At this point your map should look something like that shown in Figure 2.4.
                                                        J1
              Figure 2-4.  Subcatchments and nodes for example study area.
Now we will add the storm sewer conduits that connect our drainage system nodes to one
another. (You must have created a link's end nodes as described previously before you can create
the link.) We will begin with conduit Cl, which connects junction Jl to J2.
    l. Click the
       crosshair.
button on the Object Toolbar. The mouse cursor changes  shape to  a
    2.  Click the mouse on junction Jl. Note how the mouse cursor changes shape to a pencil.
5 If you right-click (or press Enter) after adding the first point of a subcatchment's outline, the
subcatchment will be shown as just a single point.
                                           11

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    3.  Move the mouse over to junction J2 (note how an outline of the conduit is drawn as you
       move the mouse) and  left-click to create the  conduit. You could have  cancelled the
       operation by either right clicking or by hitting the  key.

    4 .  Repeat this procedure for conduits C2 through C4.

Although all  of our conduits were drawn as straight lines, it is possible to draw a curved link by
left-clicking at intermediate points where the direction of the link changes before clicking on the
end node.

To complete the construction of our study area schematic we need to add a rain gage.

    l.  Click the Rain Gage button L-J on the Object Toolbar.

    2.  Move the mouse over the Study Area Map to where the gage should be located and left-
       click the mouse.

At this point we have completed drawing the  example study area.  Your system should look like
the one in Figure  2-1. If a rain gage, subcatchment or node is out of position you can move it by
doing the following:
              _U button is not already depressed, click it to place the map in Object Selection
    l. If the
       mode.
    2. Click on the object to be moved.
    3. Drag the object with the left mouse button held down to its new position.

To re-shape a subcatchment's outline:
    l. With the map in Object Selection mode, click on the subcatchment's centroid (indicated
       by a solid square within the subcatchment) to select it.
    2 .  Then click the
       mode.
                           button on the  Map Toolbar to put the map into Vertex  Selection
    3.   Select a vertex point on the subcatchment outline by clicking on it (note how the selected
        vertex is indicated by a filled solid square).

    4 .   Drag the vertex to its new position with the left mouse button held down.

    5.   If need be, vertices can be added or deleted from the outline by right-clicking the mouse
        and selecting the appropriate option from the popup menu that appears.

    6.   When finished, click the L—I button to return to Object Selection mode.

This same procedure can also be used to re-shape a link.
2.4    Setting Object Properties

As visual objects are added to our project, SWMM assigns them a default set of properties. To
change the value of a specific property for an object we must select the object into the Property
Editor (see Figure 2-5). There are several different ways to do this. If the Editor is already visible,
                                            12

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then you can simply click on the object or select it from the Data page of the Browser Panel of the
main window. If the Editor is not visible then you can make it appear by one of the following
actions:
    •   double-click the object on the map,
    •   or right-click on the object and select Properties from the pop-up menu that appears,
    •   or select the object from the Data page of the Browser panel and then click the Browser's
           button.
Subcatchment SI
Property Value
Name S1
X-Coordinate 5989.99
Y-Coordinate -3133.27
Description
Tag
Raingage Gagel
Outlet JJ1
Area 4
Width 400
Name of node or another
subcatchment that receives runofl


y\





!

V

                          Figure 2-5.  Property Editor window.
Whenever the Property Editor has the focus you can press the Fl key to obtain a more detailed
description of the properties listed.

Two key properties of our subcatchments that need to be  set are the rain gage that supplies
rainfall data to the subcatchment and the node  of the drainage system that receives runoff from
the subcatchment. Since all of our subcatchments utilize the same rain gage, Gagel, we can use a
shortcut method to set this property for all subcatchments at once:
    l.  From the main menu select Edit »Select All.
    2.  Then select Edit» Group Edit to make a Group Editor dialog appear (see Figure 2-6).
    3.  Select Subcatchment as the type of object to  edit, Rain Gage as the property to edit, and
       type in Gagel as the new value.
    4.  Click OK to change the rain gage of all subcatchments to Gagel. A confirmation dialog
       will appear noting that  3  subcatchments have changed.  Select "No" when asked to
       continue editing.
                                           13

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                       For objects of type

                       O with Tag equal to


                       edit the property

                       by replacing it with
      Rain Gage
      Gagel
                              OK
Cancel
Help
                             Figure 2-6. Group Editor dialog.


Because the outlet nodes vary by subcatchment, we must set them individually as follows:
    l.  Double click on subcatchment SI or select it from the Data  Browser and click the
       Browser's "S button to bring up the Property Editor.

    2.  Type Jl in the Outlet field and  press Enter. Note how a dotted line is drawn between the
       subcatchment and the node.
    3.  Click on subcatchment S2 and enter J2 as its Outlet.
    4.  Click on subcatchment S3 and enter J3 as its Outlet.

We also  wish to represent area S3 as being less developed than the others. Select S3 into the
Property  Editor and set its % Imperviousness to 25.

The junctions and outfall of our drainage system need to have invert elevations assigned to them.
As we  did with the  subcatchments, select each junction individually into  the Property Editor and
set its Invert Elevation to the value shown below6
Node
Jl
J2
J3
J4
Outl
Invert
96
90
93
88
85
Only one of the conduits in our example system has a non-default property value. This is conduit
C4, the outlet pipe, whose diameter should be 1.5 instead of 1 ft. To change its diameter, select
conduit C4 into the Property Editor and set the Max. Depth value to 1.5.
6 An alternative way to move from one object of a given type to the next in order (or to the
previous one) in the Property Editor is to hit the Page Down (or Page Up) key.
                                            14

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In order to  provide  a source  of rainfall input to our project we need to set  the rain gage's
properties. Select Gagel into the Property Editor and set the following properties:

                              Rain Format   INTENSITY
                              Rain Interval   1:00
                              Data Source   TIMESERIES
                              Series Name   TSl

As mentioned earlier, we want to simulate the response of our  study area to a 3-inch, 6-hour
design storm. A time series named TSl will contain the hourly rainfall intensities that make up
this storm. Thus we need to create a time series object and populate it with data. To do this:
    1.  From the Data Browser select the  Time Series category of objects.

    2 .  Click the *  button on the Browser to bring up the Time Series Editor dialog (see Figure
        2-7)7.

    3.  Enter TSl in  the Time Series Name field.
    4.  Enter the values shown in Figure 2-7  into the Time and Value columns of the data entry
        grid (leave the Date column blank8).

    5.  You can click the View button on the dialog to see a graph of the time series values.
        Click the OK button to accept the new time series.

Having completed the initial design of our example project it is a good idea to give it a title and
save our work to a file at this point. To do this:

    1.  Select the Title/Notes category from the Data Browser and click the ^ button.

    2.  In the Project Title/Notes dialog that appears (see Figure  2-8), enter "Tutorial Example"
        as the title  of our project and click the OK button to close  the dialog.
    3.  From the File menu select the Save As option.
    4.  In the Save As dialog that appears, select a folder and file name under which to save this
        project. We suggest naming the file tutorial.inp. (An extension of .inp will be added to
        the file  name if one is not supplied.)
    5.  Click Save to save the project to file.

The project data are saved to the file in a readable text format. You can view what the file looks
like by selecting Project » Details from the main menu. To open our project at  some later time,
you would select the  Open command from the File menu.
7 The Time  Series Editor can also be launched directly from the Rain Gage Property Editor by
selecting the editor's Series Name field and double clicking on it.
8 Leaving off the dates for a time series means that SWMM will interpret the time values as hours
from the start of the simulation. Otherwise, the time series  follows the date/time values specified
by the user.
                                            15

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 Description
     se external data file named below
 0 Enter time series data in the table below
 No dates means times are relative to start of simulation.
Date
(M/DA1







Time
(H:M)
0
1
2
3
4
5
6

Value
0
0.5
1.0
0.75
0.5
0.25
0

A






V
                                                      View...
                                                        OK
                                                       Cancel
                                                       Help
               Figure 2-7. Time Series Editor.
O Project Title/Notes
Tutorial  Example
            00®

 0 Use title line as header for printing
OK
Cancel
               Figure 2-8.  Title/Notes Editor.
                               16

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2.5     Running a Simulation

Setting Simulation Options

Before analyzing the performance of our example drainage system we need to set some options
that determine how the analysis will be carried out. To do this:

    1.  From the Data Browser, select the Options category and click the ^ button.

    2.  On the General page of the Simulation Options dialog that appears (see Figure 2-9),
        select Kinematic Wave as the flow routing method. The infiltration method should
        already be set to  Green-Ampt. The Allow Ponding option should be unchecked.

    3.  On the Dates page of the dialog, set the End Analysis time to 12:00:00.
    4.  On the Time Steps page, set the Routing Time Step to 60 seconds.

    5.  Click OK to close the  Simulation Options dialog.
             Simulation Options
               General  Dates   TimeSteps|| Dynamic Wave; Files
                  Process Models
                  0 Rainfall/Runoff

                  D Snow Melt

                     Ground water

                  0 Flow Routing

                  0 Water Quality
Miscellaneous
O Allow Ponding

HH Report Control Actions

O Report Input Summary

d] Skip Steady Periods

Minimum Conduit Slope
                  Infiltration Model

                  O Norton

                  0 Green Arnpt

                  O Curve Number
Routing Model

O Steady Flow

0 Kinematic Wave

O Dynamic Wave
                                          OK
                          Figure 2-9. Simulation Options dialog.
                                            17

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Running a Simulation

We are now ready to run the simulation. To do so, select Project » Run Simulation (or click
the      button). If there was a problem with the simulation, a Status Report will appear
describing what errors occurred. Upon successfully completing a run, there are numerous ways in
which to view the results of the simulation. We will illustrate just a few here.


Viewing the Status Report

The Status Report contains useful summary information about the results of a simulation run. To
view the report select Report » Status. A portion of the report for the system just analyzed is
shown in Figure 2-10. The full report indicates the following:
    •    The quality of the simulation is quite good, with negligible mass balance continuity errors
        for both runoff and routing (-0.05% and 0.06%,  respectively,  if all data were entered
        correctly).
    •    Of the 3 inches of rain that fell on the study area, 1.75 infiltrated into the ground and
        essentially the remainder became runoff.
    •    The Node  Flooding Summary  table (not shown in  Figure  2-11) indicates  there was
        internal flooding in the system at node J29.

    •    The Conduit  Surcharge Summary table  (also not shown in Figure 2-11)  shows that
        Conduit  C2, just downstream of node J2, was surcharged and therefore appears to be
        slightly undersized.


Viewing Results on the Map

Simulation results (as well as some design parameters, such  as subcatchment area, node invert
elevation, and link maximum depth) can be viewed in color-coded fashion on the study area map.
To view a particular variable in this fashion:

    l.  Select the Map page of the Browser panel.
    2.  Select the variables to view for Subcatchments, Nodes, and Links from the dropdown
        combo boxes  appearing in the Themes panel. In Figure  2-11, subcatchment runoff and
        link flow have been selected for viewing.

    3.  The color-coding used for a particular variable is displayed with a legend on the study
        area map. To toggle the display of a legend, select View » Legends.
    4.  To move a legend to another location, drag it with the left mouse button held down.
9 In SWMM, flooding will occur whenever the water surface at a node exceeds the maximum
defined depth or if more flow volume enters a node than can be stored or released during a given
time step. Normally such water will be lost from the system.  The option also exists to have this
water pond atop the node and be re-introduced into the drainage system when capacity exists to
do so.
                                           18

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     EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.019)
Flow Units 	  CFS
Process Models:
  Rainfall/Runoff 	  YES
  Snowmelt 	  NO
  Groundwater  	  NO
  Flow Routing 	  YES
  Ponding Allowed 	  NO
  Water Quality 	  NO
Infiltration Method 	  GREEN_AMPT
Flow Routing Method 	  KINWAVE
Starting Date  	  JUN-27-2002 00:00:00
Ending Date 	  JUN-27-2002 12:00:00
Antecedent Dry Days 	  0.0
Report Time Step 	  00:15:00
Wet Time Step  	  00:05:00
Dry Time Step  	  01:00:00
Routing Time Step 	  60.00 sec

**************************         Vo1ume
                               acre-feet
                                                    Depth
                                                   inches
   Total Precipitation ..
   Evaporation Loss 	
   Infiltration Loss ....
   Surface Runoff 	
   Final Surface Storage
   Continuity Error (%)
   **************************
   Dry Weather Inflow ...
   Wet Weather Inflow ...
   Groundwater Inflow ...
   RDII Inflow 	
   External Inflow 	
   External Outflow 	
   Internal Outflow 	
   Storage Losses 	
   Initial Stored Volume
   Final Stored Volume ..
   Continuity Error (%)  .
        Figure 2-10. Portion of the Status Report for initial simulation run.

5.  To change the color-coding and the breakpoint values for different colors, select View »
    Legends » Modify and then the pertinent class of object (or if the legend is already
    visible,  simply right-click  on it). To  view numerical  values  for the variables  being
    displayed on the map,  select Tools »  Map Display Options  and then  select the
    Annotation page of the Map  Options  dialog.  Use  the  check boxes for Subcatchment
    Values, Node Values, and Link Values to specify what kind of annotation to add.
                                        19

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    6.  The Date / Time of Day / Elapsed Time controls on the Map Browser can be used to
       move through the simulation results in time. Figure 2-11 depicts results at 5 hours and 45
       minutes into the simulation.
    7 .  You can use the controls in the Animator panel of the Map Browser (see Figure 2-11) to
       animate the map display through time.  For example, pressing the LU button will run the
       animation forward in time.
Viewing a Time Series Plot

To generate a time series plot of a simulation result:
    l.   Select Report» Graph » Time Series or simply click l£^J on the Standard Toolbar.
    2.   A Time Series Plot dialog will appear. It is used to select the objects and variables to be
        plotted.

For our example, the Time Series Plot dialog can be used to graph the flow in conduits Cl and C2
as follows (refer to Figure 2-12):
    l.   Select Links as the Object Category.
    2.   Select Flow as the Variable to plot.
       Click on conduit Cl (either on the map or in the Data Browser) and then click L.J in the
       dialog to add it to the list of links plotted. Do the same for conduit C2.
    4 .  Press OK to create the plot, which should look like the graph in Figure 2-13.

After a plot is created you can:
    •  customize its appearance by selecting Report» Customize or right clicking on the plot,
    •  copy it to the clipboard and paste it into another application by selecting Edit » Copy
       To or clicking
on the Standard Toolbar
       print it by selecting File » Print or File » Print Preview (use File » Page Setup first
       to set margins, orientation, etc.).
                                           20

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O SWMM 5 - tutorial.inp
File  Edit  View  Project  Report  Tools  Window  Help

 Data   Map
  Themes
  Subcatchments
Time of Day
 05:45:00
Elapsed Time
  Animator
               V
               >
                      <> Study Area Map
                                       S3
                           Link
                           Flow
                           0.40
                           0.80
                           1.20
                           1.60
                           CFS
                        Out1
                        T
C4
 <
                                                           J3
                                                      C3.
                                                           ,14
                                                                                       "---    J1
C2
 <
                                                                                         C1.
•i2
 D Auto-Length     Flow Units: CFS
Zoom Level: 1 00%
                                                              X,Y: 5341.116,-2444.239
       Figure 2-11.  Example of viewing color-coded results on the Study Area Map.
                                                21

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0 Time Series Plot

Start Date
06/27/2002
Time Format
Elapsed Time
Variables
Depth
Velocity
Froude No.
Capacity


End Date
06/27/2002
Object Category
Links
Links
C1
&^^^m
EJ S

V

1

•B
B
|
-------
Viewing a Profile Plot
SWMM  can generate  profile plots showing how water surface depth varies across a path  of
connected nodes and links. Let's create such a plot for the conduits connecting junction Jl to the
outfall Outl of our example drainage system. To do this:

    1. Select Report» Graph » Profile or simply click \.^4.\ on the Standard Toolbar.
    2. Either enter Jl in the Start Node field of the Profile Plot dialog that appears (see Figure

                                                                             button next to
2-14) or select it on the map or from the Data Browser and click the
the field.
                       Profile Plot
                      Create Profile

                      Start Node
                      J1
                      End Node
                      Out1
                               [+J
                            Find Path
                          Use Saved Profile
                         Save Current Profile
                                        Links in Profile
                                        1:1
                                        C2
                                        C4
                              OK           Cancel
                         (•MMMMMMMMMMJ  *
                              Figure 2-14.  Profile Plot dialog.
    3.  Do the same for node Outl in the End Node field of the dialog.
    4.  Click  the  Find Path button.  An  ordered list of the links forming a connected path
        between the specified Start and End nodes will be displayed in the Links in Profile box.
        You can edit the entries in this box if need be.
    5.  Click the OK button to create the plot, showing the water surface profile as it exists at the
        simulation time currently selected in the Map Browser (see Figure 2-15).
                                            23

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   v* Profile - Node J1 - Out1

                     Water Elevation Profile: NodeJI -Out1
        84
          1,200       1,000        800        600         400         200         0
                                         Distance (ft)
                                                                  06/27/2002 02:45:00
                         Figure 2-15. Example of a Profile Plot.
As you move through time using the Map Browser or with the Animator control, the water depth
profile on the plot will be updated. Observe how node J2 becomes flooded between hours 2 and 3
of the storm event. A Profile Plot's appearance can be customized and it can be copied or printed
using the same procedures as for a Time Series Plot.


Running a  Full Dynamic Wave Analysis

In the analysis just run we chose to use the Kinematic Wave method of routing flows through our
drainage system.  This  is  an efficient  but  simplified  approach that cannot  deal with  such
phenomena as backwater effects,  pressurized flow, flow reversal, and non-dendritic layouts.
SWMM also includes a Dynamic Wave routing procedure that can represent these conditions.
This procedure, however, requires more computation time, due to the need for smaller time steps
to maintain numerical stability.

Most of the effects  mentioned above would not apply  to our example. However we had  one
conduit, C2, which flowed full and caused its upstream junction to flood. It could be that this pipe
is actually being pressurized and could  therefore convey more  flow than was computed using
Kinematic Wave routing.  We would now like to see what would happen if we apply  Dynamic
Wave routing instead.

To run the analysis with Dynamic Wave routing:
                                                                 ^s
    1.  From the Data Browser, select the Options category and click the '^ button.

    2.  On the General page of the Simulation Options dialog that appears, select Dynamic Wave
       as the flow routing method.
                                          24

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                                                                                   10
    3.  On the Dynamic Wave page of the dialog, use the settings shown in Figure 2-16  .
              Simulation Options
                General  Dates  Time Steps  Dynamic Wave  Files
                   Inertial Terms

                   OKeep
0 Dampen
O Ignore
                   Define Supercritical Flow By

                   O Slope           O Froude No.
                  0Both
                   Force Main Equation

                   0 Hazen-Williams


                   Variable Time Step

                   Use    0
         ODarcy-Weisbach
       Adjustment Factor (%)
                   Conduit Lengthening

                   (Use 0 for No Lengthening)

                   Time Step (sec)
           Minimum Surface Area

           (Use Of or Default Area)

           Square Feet       fo~
                                           OK
                                  Help
                      Figure 2-16. Dynamic Wave simulation options.
    4.  Click OK to close the form and select Project » Run Simulation (or click the I ^ I
        button) to re-run the analysis.

If you look at the Status Report for this run, you will see that there is no longer any junction
flooding and that the peak flow carried by conduit C2 has been increased from 3.51 cfs to 4.04
cfs.
10 Normally when running a Dynamic Wave analysis, one would also want to reduce the routing
time step (on the Time Steps page of the dialog).  In this example, we will continue to use a 1-
minute time step.
                                             25

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2.6     Simulating Water Quality

In the next phase of this tutorial  we will add water quality  analysis to  our example project.
SWMM has the ability to analyze the buildup, washoff, transport and treatment of any number of
water quality constituents. The steps needed to accomplish this are:
    l.  Identify the pollutants to be analyzed.
    2.  Define the categories of land uses that generate these pollutants.
    3.  Set the parameters of buildup and washoff functions that determine the quality of runoff
        from each land use.
    4.  Assign a mixture of land uses to each subcatchment area
    5.  Define pollutant removal functions for nodes within the drainage system that contain
        treatment facilities.
We will now apply each of these steps, with the exception of number 5, to our example project11.

We will define two runoff pollutants; total suspended solids (TSS), measured as mg/L, and total
Lead, measured in ug/L. In addition, we will specify that the concentration of Lead in runoff is a
fixed fraction (0.25) of the TSS concentration. To add these pollutants to our project:
    l.  Under the Quality category in  the Data Browser,  select the Pollutants sub-category
        beneath it.

    2.  Click the  * button to add a new pollutant to the project.
    3.  In the Pollutant Editor dialog that appears (see Figure 2-17), enter TSS for the pollutant
        name and leave the other data fields at their default settings.
    4.  Click the OK button to close the Editor.

    5.  Click the  * button on the Data Browser again to add our next pollutant.
    6.  In  the  Pollutant  Editor,  enter  Lead  for  the  pollutant  name,  select  ug/L  for  the
        concentration units, enter TSS as the name of the Co-Pollutant, and enter 0.25 as the Co-
        Fraction value.
    7.  Click the OK button to close the Editor.

In SWMM, pollutants associated with runoff are generated by specific land uses  assigned to
subcatchments.  In our example, we will  define two  categories of land uses: Residential and
Undeveloped. To add these land uses to the project:
    l.  Under the Quality category in the Data Browser, select the Land Uses sub-category and
        click the * button.

    2.  In  the Land Use Editor dialog that appears (see Figure 2-18), enter Residential  in  the
        Name field and then  click the OK button.

    3.  Repeat steps  1 and 2 to create the Undeveloped land use category.
11 Aside from surface runoff, SWMM allows pollutants to be introduced into the nodes of a
drainage system  through user-defined time  series of direct inflows,  dry weather  inflows,
groundwater interflow, and rainfall dependent inflow/infiltration
                                            26

-------
 Name
 Units
 Rain Concen
 GW Concen.
 li.l Concen.
 Decay Coeff.
 Snow Only
 Co-Pollutant
 Co-Fraction
0.0

f.
0.0
0.0
 Jser-assigned name of the pollutant.
   Figure 2-17. Pollutant Editor dialog.
                                              Land Use Editor
                          General  Buildup  Washoff
                          Property
                     Value
Land Use Name
Description
                          STREET CLEANING
                           Interval
                           Availability
                           Last Cleaned
                                               Residential
                                                User assigned name of land use.
                                                     OK
                                            Cancel


0
0
                                  Help
                            Figure 2-18. Land Use Editor dialog.
Next we need to define buildup and washoff functions for TSS in each of our land use categories.
Functions for Lead are not needed since its runoff concentration was defined to be a fixed fraction
of the TSS concentration. Normally, defining these functions requires site-specific calibration.
In this example we will assume that suspended solids in Residential areas builds up at a constant
rate  of 1 pound per acre per day until a limit of 50 Ibs per acre is reached. For the Undeveloped
area we will assume that buildup is only half as much. For the washoff function, we will assume a
constant event  mean concentration of  100  mg/L for  Residential land  and 50 mg/L  for
Undeveloped  land. When runoff occurs, these  concentrations will be  maintained until  the
available buildup is exhausted. To define these functions for the Residential land use:
    l.  Select the Residential land use category from the Data Browser and click the "^ button.
    2.  In the Land Use Editor dialog, move to the Buildup page (see Figure 2-19).
    3.  Select TSS as the pollutant and POW (for Power function) as the function type.
    4 .  Assign the function a maximum buildup of 50, a rate constant of 1.0, a power of 1  and
        select AREA as the normalizer.
    5.  Move to the Washoff page of the dialog and select TSS  as the pollutant, EMC as the
        function type, and enter 100 for the coefficient. Fill the other fields with 0.
    6.  Click the OK button to accept your entries.
                                            27

-------
Now do the same for the Undeveloped land use category, except use a maximum buildup of 25, a
buildup rate constant of 0.5, a buildup power of 1, and a washoff EMC of 50.
                      Land Use Editor
                        General  Buildup  Washoff
                         Pollutant
TSS
                        Property
Value
                        Function
                        Max. Buildup
ROW
50
                        Rate Constant
                        Power/Sat. Constant
                        Normalizer
AREA
                        Buildup function: POW = power, EXP = exponential, SAT
                        = saturation.
                                          Cancel
             Help
          Figure 2-19. Defining a TSS buildup function for Residential land use.
The  final step in our water  quality example is to assign a mixture  of land uses to each
subcatchment area:
    1.  Select subcatchment SI into the Property Editor.
    2.  Select the Land Uses property and click the ellipsis button (or press Enter).
    3.  In the Land Use Assignment dialog that appears, enter 75 for the % Residential and 25
        for the % Undeveloped (see Figure 2-20). Then click the OK button to close the dialog.
    4.  Repeat the same three steps for subcatchment 5*2.
    5.  Repeat the same for subcatchment S3, except assign the land uses as  25% Residential and
        75% Undeveloped.
                                            28

-------
                        Residential
                        Undeveloped
75
25
                            	OK	        Cancel
                         L	J   L
           Help
                        Figure 2-20.  Land Use Assignment dialog.
Before we simulate the runoff quantities of TSS and Lead from our study area, an initial buildup
of TSS should be defined so it can be washed off during our single rainfall event. We can either
specify the number of antecedent dry days prior to the simulation or directly specify the initial
buildup mass on each subcatchment. We will use the former method:
    l.  From the  Options category of the Data Browser, select the Dates sub-category and click
       the & button.

    2 .  In the Simulation Options dialog that appears, enter 5 into the Antecedent Dry Days field.
    3.  Leave the other simulation options the same as they  were for the dynamic wave flow
       routing we just completed.
    4.  Click the  OK button to close the dialog.                                  	
Now run the simulation by selecting Project » Run Simulation or by clicking
Standard Toolbar.
                                      on the
When the run is completed, view its Status Report. Note that two new sections have been added
for Runoff Quality  Continuity  and Quality Routing Continuity.  From  the  Runoff  Quality
Continuity table we see that there was an initial buildup of 47.5 Ibs of TSS on the study area and
an additional 2.2 Ibs of buildup added during the  dry periods of the simulation. About 47.9 Ibs
were washed off during the rainfall event. The quantity of Lead washed off is a  fixed percentage
(25% times 0.001 to convert from mg to ug) of the TSS as was specified.

If you plot the runoff concentration of TSS for subcatchment SI and S3 together on the same time
series graph, as in Figure 2-21, you will see the difference  in concentrations resulting from the
different mix of land uses in these two areas. You can also see  that the  duration over which
pollutants are washed off is much shorter than the duration of the entire runoff hydrograph (i.e., 1
hour versus about 6 hours). This results from having exhausted the available buildup of TSS over
this period of time.
                                           29

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& Graph - Subcatchment TSS Q©®
i
nn n
0U>U
80.0
70.0-
^60.0-
0 50.0
5
M 40.0
v>
"~ 30.0
20.0-
10.0-









— -








Subcatchment TSS


catch S3 |




\
y
I
I
T
1
0 2












































4 6 8 10 12 14
Elapsed Time (hours)
          Figure 2-21.  TSS concentration of runoff from selected subcatchments.
2.7    Running a Continuous Simulation

As  a final exercise in this tutorial we  will demonstrate how to run a long-term continuous
simulation using a historical rainfall record and how to perform a statistical frequency analysis on
the results. The rainfall record will come from a file named sta310301.dat that was included with
the  example data sets provided with EPA SWMM. It contains several years of hourly rainfall
beginning in January 1998. The data are  stored in the National Climatic Data Center's DSI 3240
format, which SWMM can automatically recognize.

To run a continuous simulation with this rainfall record:
    i.  Select the rain gage Gage I into the Property Editor.
    2.  Change the selection of Data Source to FILE.
    3.  Select the File Name  data field and click the ellipsis button (or press the Enter key) to
        bring up a standard Windows File Selection dialog.
    4.  Navigate to the folder where the SWMM example files were stored, select the file named
        sta310301.dat, and click Open to select the file and close the dialog.
    5.  In the Station No. field of the Property Editor enter 310301.

    6.  Select the Options category in the Data Browser and click the "S button to bring up the
        Simulation Options form.

    7.  On the General page of the form,  select Kinematic Wave as the Routing Method (this will
        help speed up the computations).
    8.  On the Date page of the form, set both the Start Analysis and Start Reporting dates to
        01/01/1998, and set the End Analysis date to 01/01/2000.
                                           30

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    9.   On the Time Steps page of the form, set the Routing Time Step to 300 seconds.
    10. Close the Simulation Options form by clicking the OK button and start the simulation by
        selecting Project» Run Simulation (or by clicking L!L\ on the Standard Toolbar).

After our  continuous simulation is completed we can perform a statistical frequency analysis on
any of the variables produced as output. For example, to determine the distribution of rainfall
volumes within each storm event over the two-year period simulated:
    l.  Select Report» Statistics or click the
       button on the Standard Toolbar.
    2.  In the Statistics Selection dialog that appears, enter the values shown in Figure 2-22.
    3.  Click the OK button to close the form.
                       O Statistics Selection
                         Object Category

                         Object Name

                         Variable Analyzed

                         Event Time Period

                         Statistic

                          Event Thresholds

                           Precipitation

                           Event Volume

                           Separation Time
                                              System
   Precipitation
  Event-Dependent
   Total
                               OK
Cancel
Help
                          Figure 2-22.  Statistics Selection dialog.
The  results of this request will be  a Statistics Report form (see  Figure 2-23) containing  four
tabbed pages: a Summary page, an Events page containing a rank-ordered listing of each event, a
Histogram page containing a plot of the occurrence frequency versus event magnitude, and a
Frequency Plot page that plots event magnitude versus cumulative frequency.
                                             31

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         <> Statistics - System  Precipitation
Ed
         I Surnmarvj Events  Histogram  Frequency Plot
            SUMMARY
                             STATISTICS
            Obj ect  	  System
            Variable 	  Precipitation  (in/hr)
            Event Period  	  Variable
            Event Statistic  	  Total  (in)
            Event Threshold  	  Precipitation > 0.0000   (in/hr)
            Event Threshold  	  Event Volume  > 0.0000  (in)
            Event Threshold  	  Separation  Time >= 6.0   (hr)
            Period of Record 	  01/01/1998  to 01/01/3000

            Number of Events 	  213
            Event Frequency*	  0.076
            Minimum Value  	  0.010
            Maximum Value  	  3.3SO
            Mean Value  	  0.309
            Std.  Deviation	  0.449
            Skewness Coeff	  3.161

            *Fraction of  all reporting periods belonging to an  event.
                         Figure 2-23. Statistical Analysis report.

The summary page shows that there were a total of 213 rainfall events. The Events page shows
that the largest rainfall event had a  volume of 3.35 inches and occurred over a 24- hour period.
There were no events that matched the 3-inch, 6-hour design storm event used in our previous
single-event analysis that had produced some internal flooding. In fact, the  status report for this
continuous simulation indicates  that there were no flooding or  surcharge occurrences over the
simulation period.

We have only touched the surface of SWMM's capabilities. Some additional features of the
program that you will find useful include:
    •    utilizing additional types of drainage elements, such as storage units, flow dividers,
        pumps, and regulators, to model more complex types of systems
    •    using control rules to simulate real-time operation of pumps and regulators
    •    employing different types of externally-imposed inflows at drainage system nodes, such
        as direct time series inflows, dry weather inflows, and rainfall-derived infiltration/inflow
    •    modeling groundwater interflow between aquifers beneath subcatchment areas and
        drainage  system nodes
    •    modeling snow fall accumulation and melting within subcatchments
    •    adding calibration data to a project so that simulated results can be compared with
        measured values
    •    utilizing a background street, site plan, or topo map to assist in laying out a system's
        drainage  elements and to help relate simulated results to real-world locations.
You can find more information on these  and other features in the remaining chapters of this
manual.
                                          32

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CHAPTER 3 - SWMM's CONCEPTUAL MODEL
This chapter discusses how SWMM models the objects and operational parameters that constitute
a stormwater drainage system. Details about how this information is entered into the program
are presented in later chapters. An overview is also given on the computational methods that
SWMM uses  to simulate the hydrology,  hydraulics and water quality transport behavior of a
drainage system.
3.1    Introduction

SWMM conceptualizes a drainage system as a series of water and material flows between several
major environmental compartments. These compartments and the SWMM objects they contain
include:
    •  The Atmosphere compartment, from which precipitation falls and pollutants are
       deposited onto the land surface compartment. SWMM uses Rain Gage objects to
       represent rainfall inputs to the system.
    •  The Land Surface compartment, which is represented through one or more Subcatchment
       objects. It receives precipitation from the Atmospheric compartment in the form of rain
       or snow; it sends  outflow in the form of infiltration to the Groundwater compartment and
       also as surface runoff and pollutant loadings to the Transport compartment.
    •  The Groundwater compartment receives infiltration from the Land Surface compartment
       and transfers a portion of this inflow to the Transport compartment. This compartment is
       modeled using Aquifer objects.
    •  The Transport compartment contains a network of conveyance elements (channels, pipes,
       pumps, and regulators) and storage/treatment units that transport water to outfalls or to
       treatment facilities. Inflows to this compartment can come from surface runoff,
       groundwater interflow, sanitary dry weather flow, or from user-defined hydrographs. The
       components of the Transport compartment are modeled with Node and Link objects

Not all compartments need appear in a particular SWMM model. For example, one could model
just the transport compartment, using pre-defined hydrographs as inputs.
3.2    Visual Objects

Figure 3-1 depicts how a collection of SWMM's visual objects might be arranged together to
represent a stormwater drainage system. These objects can be displayed on a map in the SWMM
workspace. The following sections describe each of these objects.
                                          33

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                    Raingage  Kp
                                                     Subcatchment
                          Storage Unit
                               Divider
Junction

Conduit
                 Outfall
          Regulator
                                         Pump
         Figure 3-1.  Example of physical objects used to model a drainage system.
3.2.1    Rain Gages

Rain Gages supply precipitation data for one or more subcatchment areas in a study region. The
rainfall  data  can be either a user-defined time series or come from  an  external file.  Several
different popular rainfall file formats currently in use are supported, as well as a standard user-
defined  format.

The principal input properties of rain gages include:
    •    rainfall data type (e.g., intensity, volume, or cumulative volume)
    •    recording time interval (e.g., hourly, 15-minute, etc.)
    •    source of rainfall data (input time series or external file)
    •    name of rainfall data source


3.2.2    Subcatchments

Subcatchments are  hydrologic units  of land whose topography and drainage system elements
direct surface runoff to a single discharge point. The user is responsible for dividing a study area
into an  appropriate  number of  Subcatchments, and for identifying the  outlet  point of each
subcatchment. Discharge  outlet  points can  be either nodes of the drainage system  or other
Subcatchments.

Subcatchments can be  divided  into  pervious and impervious subareas. Surface runoff can
infiltrate into the upper soil zone of the pervious subarea, but not through the impervious subarea.
Impervious areas are themselves divided into two subareas - one that contains depression storage
and another that does not.  Runoff flow from  one subarea in a subcatchment can be routed to the
other subarea, or both subareas can drain to the subcatchment outlet.
                                           34

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Infiltration of rainfall from the pervious area of a subcatchment into the unsaturated upper soil
zone can be described using three different models:
    •  Horton infiltration
    •  Green-Ampt infiltration
    •  Curve Number infiltration
To model the accumulation, re-distribution, and melting of precipitation that falls as snow on a
subcatchment, it must be assigned a Snow Pack object. To model groundwater flow between  an
aquifer underneath the subcatchment and a node of the drainage system, the subcatchment must
be assigned a set of Groundwater parameters. Pollutant buildup and washoff from subcatchments
are associated with the  Land Uses assigned  to  the  subcatchment. Capture and retention  of
rainfall/runoff using different types  of low impact development practices (such as bio-retention
cells, infiltration trenches, porous pavement, vegetative swales, and rain barrels) can be modeled
by assigning a set of predesigned LID controls to the subcatchment.
The other principal input parameters for subcatchments include:
    •  assigned rain gage
    •  outlet node or subcatchment
    •  assigned land uses
    •  tributary surface area
    •  imperviousness
    •  slope
    •  characteristic width of overland flow
    •  Manning's n for overland flow on both pervious and impervious  areas
    •  depression storage in both pervious and impervious areas
    •  percent of impervious area with no depression storage.

3.2.3  Junction Nodes
Junctions are drainage system nodes where links join together. Physically they can represent the
confluence of natural surface channels, manholes in a sewer system, or pipe connection fittings.
External  inflows  can enter  the system at junctions. Excess  water at a junction can become
partially pressurized while connecting conduits are surcharged and can either be lost from the
system or be allowed to pond atop the junction and subsequently drain back into the junction.
The principal input parameters for a junction are:
    •  invert elevation
    •  height to ground surface
    •  ponded surface area when flooded (optional)
    •  external inflow data (optional).
                                           35

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3.2.4  Outfall Nodes

Outfalls are terminal nodes of the drainage system used to define final downstream boundaries
under Dynamic Wave flow routing. For other types of flow  routing they behave as a junction.
Only a single link can be connected to an outfall node.

The  boundary conditions  at  an outfall  can be described by any one of the following stage
relationships:
    •  the critical or normal flow depth in the connecting conduit
    •  a fixed stage elevation
    •  a tidal stage described in a table of tide height versus hour of the day
    •  a user-defined time series of stage versus time.

The principal input parameters for outfalls include:
    •  invert elevation
    •  boundary condition type and stage description

    •  presence of a flap gate to prevent backflow through the outfall.


3.2.5  Flow Divider Nodes

Flow Dividers are drainage system nodes that divert inflows to a specific conduit in a prescribed
manner. A flow divider can have no more than two conduit links on its discharge side. Flow
dividers are only active under Kinematic Wave routing and are treated as simple junctions under
Dynamic Wave routing.

There are four types of flow dividers, defined by the manner in which inflows are diverted:

    Cutoff Divider:      diverts all inflow above a defined cutoff value.
    Overflow Divider.   diverts all inflow above the flow capacity of the non-diverted
                       conduit.
    Tabular Divider:    uses a table that expresses diverted flow as a function of total
                       inflow.
    Weir Divider.       uses a weir equation to compute diverted flow.

The flow diverted through  a weir divider is computed by the following equation
where Q&v = diverted flow, Cw = weir coefficient, Hw = weir height and /is computed as


     f _ -e^m   !*^min

         *^max   A^min
                                           36

-------
where  Qin is  the  inflow to the divider,  Qmin is  the  flow at which diversion begins,  and
O   =C  7/1'5
  •
         w   w
                    user-specified parameters for the weir divider are Qmin Hw, and Cw.
The principal input parameters for a flow divider are:
    •  junction parameters (see above)
    •  name of the link receiving the diverted flow
    •  method used for computing the amount of diverted flow.


3.2.6  Storage Units

Storage Units are drainage  system nodes that provide  storage volume.  Physically they could
represent  storage facilities as small as a catch basin or as  large as a lake.  The volumetric
properties of a storage unit are described by a function or table of surface area versus height.

The principal input parameters for storage units include:
    •  invert elevation
    •  maximum depth

    •  depth-surface area data
    •  evaporation potential
    •  ponded surface area when flooded (optional)
    •  external inflow data (optional).


3.2.7  Conduits

Conduits are pipes  or channels that move water from one node to another in the conveyance
system. Their cross-sectional shapes can be selected from a variety of standard open and closed
geometries as listed in Table 3-1.

Most open channels can be represented with a rectangular, trapezoidal, or user-defined irregular
cross-section shape. For the  latter, a  Transect object is  used  to define  how  depth varies with
distance across the  cross-section (see  Section 3.3.5 below).  The most common shapes for new
drainage and sewer pipes are circular, elliptical, and arch pipes. They come in  standard sizes that
are published by the American  Iron and Steel Institute in Modern  Sewer Design and by the
American Concrete Pipe Association in the Concrete Pipe Design  Manual. The Filled Circular
shape allows the bottom of a circular pipe  to be  filled  with  sediment  and thus limit its flow
capacity. The Custom Closed Shape allows any closed  geometrical shape that is symmetrical
about the center line to be defined by supplying a Shape Curve for the cross section (see  Section
3. 3. 11 below).
                                            37

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Table 3-1. Available cross section shapes for conduits
Name
Circular
Filled
Circular

Rectangular -
Open

Triangular
Vertical
Ellipse
Parabolic
Rectangular-
Triangular
Modified
Baskethandle

Horseshoe
Catenary
Baskethandle
Irregular
Natural
Channel
Parameters
Full Height
Full Height,
Filled Depth

Full Height,
Width

Full Height,
Top Width
Full Height,
Max. Width
Full Height,
Top Width
Full Height
Top Width,
Triangle
Height
Full Height,
Bottom
Width,

Full Height
Full Height
Full Height
Transect
Coordinates

Shape
w





V
0
u

m
&

a
a
o
v/
v\/
Name
Circular Force
Main
Rectangular -
Closed

Trapezoidal

Horizontal
Ellipse
Arch
Power
Rectangular-
Round
Egg

Gothic
Semi-
Elliptical
Semi-Circular
Custom
Closed Shape

Parameters
Full Height,
Roughness
Full Height,
Width

Full Height,
Base Width,
Side Slopes

Full Height,
Max. Width
Full Height,
Max. Width
Full Height,
Top Width,
Exponent
Full Height
Top Width,
Bottom
Radius
Full Height

Full Height
Full Height
Full Height
Full Height,
Shape Curve
Coordinates
Shape
•



w

»
0
V

LJ
0

o
0
«
7 N
tj^jg
                                    38

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SWMM uses the Manning equation to express the relationship between flow rate (0, cross-
sectional area (A), hydraulic radius (R), and slope (S) in all conduits. For standard U.S. units,
          n

where n  is the  Manning roughness coefficient. The slope S is interpreted as either the conduit
slope or the friction slope (i.e., head loss per unit length), depending on the flow routing method
used.

For pipes with Circular Force Main cross-sections either the Hazen- Williams or Darcy-Weisbach
formula is used in place of the Manning equation for fully pressurized flow. For U.S. units the
Hazen-Williams formula is:

    Q = 1.318CAR063S054

where C is the Hazen-Williams C-factor which varies inversely with surface roughness and is
supplied as one of the cross-section's parameters. The Darcy-Weisbach formula is:
                l/2cil/2
where g is the acceleration of gravity and/is the Darcy-Weisbach friction factor. For turbulent
flow, the latter is determined from the height of the roughness elements on the walls of the pipe
(supplied  as an input parameter)  and the flow's Reynolds Number using the Colebrook-White
equation. The choice of which equation to use is a user-supplied option.

 ''T'1
 W     A conduit does not have to be assigned a Force Main shape for it to pressurize. Any of
        the closed cross-section shapes can potentially pressurize  and  thus  function as force
        mains that use the Manning equation to compute friction losses.

A conduit can also be designated  to act as a culvert if a Culvert Inlet Geometry code number is
assigned to it. These code numbers are listed in Table A10 of Appendix A. Culvert conduits are
checked continuously  during dynamic wave flow routing to see if they  operate under  Inlet
Control as defined  in  the Federal Highway Administration's publication Hydraulic  Design of
Highway  Culverts  (Publication No. FHWA-NHI-01-020,  May  2005).  Under inlet control a
culvert  obeys a particular  flow versus inlet depth rating curve whose shape depends  on the
culvert's shape, size, slope,  and inlet geometry.

The principal input parameters for conduits are:

    •   names of the inlet and outlet nodes

    •   offset height or elevation above the inlet and outlet node inverts

    •   conduit length
    •   Manning's roughness

    •   cross-sectional geometry
                                            39

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    •   entrance/exit losses (optional)
    •   presence of a flap gate to prevent reverse flow (optional).

3.2.8   Pumps

Pumps are links used to lift water to higher elevations. A pump curve  describes the relation
between a pump's flow rate and conditions at its inlet and outlet nodes. Four different types of
pump curves are supported:
Tvpel
An off-line pump with a wet
well where flow increases
incrementally with available
wet well volume
Type2
An in-line pump where flow
increases incrementally with
inlet node depth.
Type3
An in-line pump where flow
varies continuously with
head difference between the
inlet and outlet nodes.
Tvpe4
A variable speed in-line
pump where flow varies
continuously with inlet node
depth.
                                            Volume
                                            Depth
                                             Head
                                            Depth
Ideal
An "ideal"  transfer pump whose flow rate equals the inflow rate at its inlet node. No curve is
required. The pump must be the only outflow link from  its inlet node. Used mainly  for
preliminary design.

The on/off  status of pumps can be controlled dynamically by specifying startup and shutoff water
depths at the inlet node or through user-defined Control Rules. Rules can also be used to simulate
variable speed drives that modulate pump flow.
                                           40

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The principal input parameters for a pump include:
    •   names of its inlet and outlet nodes
    •   name of its pump curve
    •   initial on/off status
    •   startup and shutoff depths.

3.2.9   Flow Regulators
Flow Regulators are structures or devices used to control and divert flows within a conveyance
system. They are typically used to:
    •   control releases from storage facilities
    •   prevent unacceptable surcharging
    •   divert flow to treatment facilities and interceptors
SWMM can model the following types of flow regulators: Orifices, Weirs, and Outlets.
Orifices
Orifices are used to model outlet and diversion structures in drainage systems, which are typically
openings  in  the wall  of  a manhole, storage  facility, or  control  gate. They  are  internally
represented in SWMM as a link connecting two nodes. An orifice can have either a circular or
rectangular shape, be located either at the bottom or along the side of the upstream node, and
have a flap gate to prevent backflow.
Orifices can be used as storage unit outlets under all types of flow routing. If not attached to a
storage unit node, they can only be used in drainage networks that are analyzed with Dynamic
Wave flow routing.
The flow through a fully submerged orifice is computed as
where Q = flow rate, C = discharge coefficient, A = area of orifice opening, g = acceleration of
gravity, and h = head difference across the orifice. The height of an orifice's opening can  be
controlled dynamically through user-defined Control Rules. This feature can be used to model
gate openings and closings.
The principal input parameters for an orifice include:
    •    names of its inlet and outlet nodes
    •    configuration (bottom or side)
    •    shape (circular or rectangular)
    •    height or elevation above the inlet node invert
    •    discharge coefficient
                                            41

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       time to open or close.
Weirs
Weirs, like orifices, are used to model outlet and diversion structures in a drainage system. Weirs
are typically located in a manhole, along the side of a channel, or within a storage unit. They are
internally represented in SWMM as a link connecting two nodes, where the weir itself is placed at
the upstream node. A flap gate can be included to prevent backflow.

Four varieties of weirs are available, each incorporating a different formula for computing flow
across the weir as listed in Table 3-2.

           Table 3-2. Available types of weirs.
Weir Type Cross Section Shape Flow Formula
Transverse
Side flow
V-notch
Trapezoidal
Rectangular
Rectangular
Triangular
Trapezoidal
CwLh^
CwLh^
CwSh5'2
CwLh*/2+CwsSh5/2
Cw = weir discharge coefficient, L = weir length, S = side slope of
V-notch or trapezoidal weir, h = head difference across the weir,
Cws = discharge coefficient through sides of trapezoidal weir.
Weirs can be used as storage unit outlets under all types of flow routing. If not attached to a
storage unit, they can only be used in drainage networks that are analyzed with Dynamic Wave
flow routing.

The height of the weir crest above the inlet node invert can be  controlled dynamically through
user-defined Control Rules. This feature can be used to model inflatable dams.

The principal input parameters for a weir include:
    •  names of its inlet and outlet nodes
    •  shape and geometry
    •  crest height or elevation above the inlet node invert
    •  discharge coefficient.

Outlets

Outlets are flow control  devices that are typically used to control outflows from storage units.
They are used  to  model  special head-discharge relationships that cannot be characterized  by
pumps, orifices, or weirs. Outlets are internally represented in SWMM as a link connecting two
nodes. An outlet can also have a flap gate that restricts flow to only one direction.

Outlets attached to storage units are active under all types of flow routing. If not attached to a
storage unit, they  can only be used in drainage networks analyzed with Dynamic Wave flow
routing.
                                            42

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A user-defined rating curve  determines  an outlet's discharge flow as a function of either the
freeboard depth above the outlet's opening or the head difference across it. Control Rules can be
used to dynamically adjust this flow when certain conditions exist.

The principal input parameters for an outlet include:
    •  names of its inlet and outlet nodes
    •  height or elevation above the inlet node invert
    •  function or table containing its head (or depth) - discharge relationship.


3.2.10 Map Labels

Map Labels are optional text labels added to SWMM's Study Area Map to help identify particular
objects or regions of the map. The labels can be drawn in any Windows font, freely edited and be
dragged to any position on the map.
3.3     Non-Visual Objects

In addition to physical objects that can be displayed visually on a map, SWMM utilizes several
classes of non-visual data objects to describe additional characteristics and processes within a
study area.


3.3.1 Climatology

Temperature

Air temperature data are used when simulating snowfall and snowmelt processes during runoff
calculations. They can also be used to compute daily evaporation rates.  If these processes are not
being simulated then temperature data are not required. Air temperature data can be supplied to
SWMM from one of the following sources:

    •   a user-defined time series of point values (values at intermediate times are interpolated)
    •   an external climate file containing daily minimum  and maximum values (SWMM fits a
        sinusoidal curve through these values depending on  the day of the year).
For user-defined time series, temperatures are in degrees F for US units and degrees C  for metric
units. The external climate file can also be used to directly supply evaporation and wind speed as
well.

Evaporation

Evaporation can  occur  for standing water on  subcatchment surfaces, for subsurface water in
groundwater aquifers, and for water held in storage units. Evaporation rates can be stated as:
    •   a single constant value
    •   a set of monthly average values
    •   a user-defined time series of daily values
                                            43

-------
    •  values computed from the daily temperatures contained in an external climate file
    •  daily values read directly from an external climate file.
If rates are read directly from a climate file, then a set of monthly pan coefficients should also be
supplied  to  convert the pan  evaporation data to free water-surface  values. An option is also
available to allow evaporation only during periods with no precipitation.

Wind Speed

Wind speed is an optional climatic variable that is only used for snowmelt calculations.  SWMM
can use either  a set of monthly average speeds or wind speed data contained in the same climate
file used for daily minimum/maximum temperatures.

Snowmelt

Snowmelt parameters  are climatic variables that  apply across the entire  study area when
simulating snowfall and snowmelt. They include:
    •  the air temperature at which precipitation falls as  snow
    •  heat exchange properties of the snow surface
    •  study area elevation, latitude, and longitude correction

Areal Depletion

Areal depletion  refers to  the tendency of accumulated snow to melt non-uniformly over the
surface of a subcatchment.  As the melting process proceeds, the area covered by  snow gets
reduced.  This behavior is  described by an Areal Depletion Curve that plots the  fraction of total
area that remains snow covered against the ratio of the actual snow depth to the depth at which
there is 100% snow cover. A typical ADC for a natural  area is shown in Figure 3-2. Two such
curves can be supplied to SWMM, one for impervious areas and another for pervious areas.
                                    02     O.t     06     OS
                                        Radon Snow co^red
                                                              |JO
                   Figure 3-2.  Areal Depletion curve for a natural area.
                                           44

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3.3.2  Snow Packs

Snow Pack objects contain parameters that characterize the  buildup, removal, and melting of
snow over three types of sub-areas within a subcatchment:
    •  The Plowable  snow pack area consists of a user-defined fraction of the total impervious
       area.  It is meant to represent such areas as streets and parking lots where plowing  and
       snow removal  can be done.
    •  The Impervious snow pack area covers the remaining impervious area of a subcatchment.
    •  The Pervious snow pack area encompasses the entire pervious area of a subcatchment.

Each of these three areas is characterized by the following parameters:
    •  Minimum and maximum snow melt coefficients
    •  minimum air temperature for snow melt to occur
    •  snow depth above which 100% areal coverage occurs
    •  initial snow depth
    •  initial and maximum free water content in the pack.

In addition,  a set  of  snow removal  parameters can be  assigned to the  Plowable area. These
parameters consist of the depth  at which snow removal begins and the fractions of snow moved
onto various other areas.

Subcatchments are assigned a snow pack object through their Snow Pack property. A single snow
pack object  can be applied to any  number of subcatchments. Assigning a  snow pack to  a
subcatchment simply  establishes the melt parameters  and  initial  snow conditions for that
subcatchment. Internally, SWMM creates a "physical" snow pack for each subcatchment, which
tracks snow accumulation  and melting for that particular subcatchment based on its snow pack
parameters, its amount of pervious and impervious area, and the precipitation history it sees.


3.3.3  Aquifers

Aquifers are  sub-surface groundwater  areas used to  model the vertical movement  of water
infiltrating from the subcatchments that  lie  above them. They  also permit the infiltration of
groundwater into the drainage system, or exfiltration of surface water from the drainage system,
depending on the hydraulic gradient that exists. The same aquifer object can be shared by several
subcatchments.  Aquifers are only required in models that need to explicitly  account for  the
exchange of groundwater with the drainage system or to establish baseflow and recession curves
in natural channels and non-urban systems.

Aquifers are  represented using  two zones - an  un-saturated  zone and a saturated zone.  Their
behavior is   characterized  using  such parameters  as  soil  porosity,  hydraulic  conductivity,
evapotranspiration depth, bottom elevation, and  loss rate to deep groundwater. In addition,  the
initial water table elevation and initial moisture content of the unsaturated zone must be supplied.

Aquifers are  connected to  subcatchments and  to  drainage system  nodes   as defined in  a
subcatchment's Groundwater Flow property. This property also contains parameters that govern
the rate of groundwater flow between the aquifer's saturated zone and the drainage system node.
                                           45

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3.3.4   Unit Hydrographs

Unit Hydrographs (UHs) estimate rainfall-dependent infiltration/inflow (RDII)  into  a  sewer
system. A UH set contains up to three such hydrographs, one for a short-term response, one for an
intermediate-term response, and one for a long-term response. A UH group can have up to 12 UH
sets, one  for each month of the year. Each UH group is considered as  a separate object by
SWMM, and is assigned its own unique name along with the name of the rain gage that supplies
rainfall data to it.

Each unit hydrograph, as shown in Figure 3-3, is defined by three parameters:
    •   R: the fraction of rainfall volume that enters the sewer system
    •   T: the time from the onset of rainfall to the peak of the UH in hours
    •   K: the ratio of time to recession of the UH to the time to peak
                           Qpeak
                                                      T(l-fK)
                                           Tune
                          Figure 3-3. An RDII unit hydrograph
Each unit hydrograph can also have a set of Initial Abstraction (IA) parameters associated with it.
These determine how much  rainfall is lost to  interception  and depression storage before any
excess rainfall is  generated and  transformed into RDII flow by the hydrograph.  The  IA
parameters consist of:
    •   a maximum possible depth of IA (inches or mm),

    •   a recovery rate (inches/day or mm/day) at which stored IA is depleted during dry periods,
    •   an initial depth of stored IA (inches or mm).
To  generate RDII  into  a  drainage  system node, the node  must identify (through its Inflows
property) the UH group and the area of the surrounding sewershed that contributes RDII flow.
       An alternative to using unit hydrographs to define RDII flow is to create an external RDII
       interface file, which contains RDII time series data.
3.3.5  Transects

Transects refer to the geometric data that describe how bottom elevation varies with horizontal
distance  over the  cross section of a natural channel  or  irregular-shaped conduit. Figure 3-4
displays an example transect for a natural channel.
                                            46

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                                      » Overbank • Channel
                 804
                            20     40     60     SO     100     120    140
                 799 .
                    Figure 3-4. Example of a natural channel transect.

Each transect must be given a unique name. Conduits refer to that name to represent their shape.
A special Transect Editor is available for editing the station-elevation data of a transect. SWMM
internally converts these data into tables of area, top width, and hydraulic radius versus channel
depth.  In  addition,  as shown  in the diagram  above, each transect can  have  a left and right
overbank section whose Manning's roughness can be different from that of the main channel. This
feature can provide more realistic estimates of channel conveyance under high flow conditions.


3.3.6    External Inflows

In addition to inflows originating from subcatchment runoff and groundwater,  drainage system
nodes can receive three other types of external inflows:
    •    Direct Inflows - These are user-defined time series of inflows added directly into a node.
        They can be used to perform flow and water quality routing in the absence of any runoff
        computations (as in a study area where no subcatchments are defined).
    •    Dry  Weather Inflows  -  These   are  continuous inflows that typically  reflect  the
        contribution from  sanitary sewage in sewer systems or base flows in pipes  and stream
        channels. They are represented by an average inflow rate that can be periodically adjusted
        on a monthly, daily, and hourly basis by applying Time Pattern multipliers to this average
        value.
    •    Rainfall-Dependent Infiltration/Inflow (RDII) - These are stormwater flows that enter
        sanitary  or  combined sewers due  to "inflow" from direct  connections of downspouts,
        sump pumps, foundation drains, etc. as well as "infiltration" of subsurface water through
        cracked pipes, leaky joints, poor manhole connections,  etc.  RDII can be computed for a
        given  rainfall record based on set of triangular unit hydrographs (UH)  that determine a
        short-term,  intermediate-term, and  long-term inflow response for each time period of
        rainfall.  Any  number  of UH sets  can be  supplied for different sewershed areas  and
        different months  of the  year. RDII flows can also be specified in an  external  RDII
        interface file.

Direct,  Dry  Weather, and  RDII inflows are properties associated  with each type  of drainage
system  node (junctions, outfalls, flow dividers, and  storage units)  and can be specified  when
                                           47

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nodes are edited. It is also possible to make the outflows generated from an upstream drainage
system be the inflows to a downstream system by using interface files. See Section 11.7 for
further details.
3.3.7  Control Rules

Control Rules determine how pumps and regulators in the drainage system will be adjusted over
the course of a simulation. Some examples of these rules are:

Simple time-based pump control:

RULE Rl
IF SIMULATION TIME > 8
THEN PUMP 12 STATUS = ON
ELSE PUMP 12 STATUS = OFF

Multiple-condition orifice gate control:

RULE R2A
IF NODE 23 DEPTH > 12
AND LINK 165 FLOW > 100
THEN ORIFICE R55 SETTING = 0.5

RULE R2B
IF NODE 23 DEPTH > 12
AND LINK 165 FLOW > 200
THEN ORIFICE R55 SETTING =1.0

RULE R2C
IF NODE 23 DEPTH <= 12
OR LINK 165 FLOW <= 100
THEN ORIFICE R55 SETTING = 0

Pump station operation:

RULE R3A
IF NODE Nl DEPTH > 5
THEN PUMP N1A STATUS = ON

RULE R3B
IF NODE Nl DEPTH > 7
THEN PUMP NIB STATUS = ON

RULE R3C
IF NODE Nl DEPTH <= 3
THEN PUMP N1A STATUS = OFF
AND PUMP NIB STATUS = OFF
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Modulated weir height control:

RULE R4
IF NODE N2 DEPTH >= 0
THEN WEIR W25 SETTING = CURVE C25

Appendix C.3  describes the control rule format in more detail and the special Editor used to edit
them.


3.3.8   Pollutants

SWMM  can simulate the generation, inflow  and transport  of any number  of user-defined
pollutants. Required information for each pollutant includes:
    •  pollutant name
    •  concentration units (i.e., milligrams/liter, micrograms/liter, or counts/liter)
    •  concentration in rainfall
    •  concentration in groundwater

    •  concentration in direct infiltration/inflow
    •  concentration in dry weather flow

    •  first-order decay coefficient.

Co-pollutants can also be defined in SWMM. For example, pollutant X can have a co-pollutant Y,
meaning that  the runoff concentration  of X  will  have some  fixed  fraction of the runoff
concentration of Y added to it.

Pollutant buildup  and washoff from subcatchment areas are determined by the land uses assigned
to those areas. Input loadings of pollutants to the drainage system can also originate from external
time series inflows as well as from dry weather inflows.


3.3.9   Land Uses

Land Uses are categories of development activities or land surface characteristics assigned to
subcatchments. Examples of land use activities  are  residential, commercial, industrial,  and
undeveloped.  Land  surface characteristics might   include  rooftops,  lawns,  paved roads,
undisturbed  soils, etc.  Land uses are used  solely  to  account  for spatial variation in pollutant
buildup and washoff rates within subcatchments.

The  SWMM user has many options for defining land uses and assigning them to  subcatchment
areas. One approach is to assign a mix of land uses for each subcatchment, which results in all
land uses within  the subcatchment having  the same pervious and impervious characteristics.
Another approach is to create subcatchments that have a single land use classification along with
a distinct set of pervious and impervious characteristics that reflects the classification.
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The following processes can be defined for each land use category:
    •   pollutant buildup
    •   pollutant washoff
    •   street cleaning.

Pollutant Buildup

Pollutant buildup that accumulates within a land use  category is described (or "normalized") by
either a mass per unit of subcatchment area or per  unit of curb length. Mass  is expressed  in
pounds for US units and kilograms for metric units.  The amount of buildup is a function of the
number of preceding dry weather days and can be computed using one of the following functions:

Power Function: Pollutant buildup (B) accumulates proportionally to time (t)  raised to some
power, until a maximum limit is achieved,
where C; = maximum buildup possible (mass per unit of area or curb length), C2 = buildup rate
constant, and C3 = time exponent.

Exponential Function:  Buildup follows  an  exponential  growth  curve  that  approaches  a
maximum limit asymptotically,
where C; = maximum buildup possible (mass per unit of area or curb length) and C2 = buildup
rate constant (I/days).

Saturation Function:  Buildup begins at a linear rate that continuously declines with time until a
saturation value is reached,
        C2+t

where  C;  = maximum buildup possible  (mass per unit area or curb length) and  C2 = half-
saturation constant (days to reach half of the maximum buildup).

External Time Series:  This option allows one to use a Time Series to describe  the rate  of
buildup per day as a function of time.  The values placed in the time series would have units  of
mass per unit area (or curb length) per day. One can also provide a maximum possible buildup
(mass per unit area or curb length) with this option and a scaling factor that multiplies the time
series values.

Pollutant Washoff

Pollutant washoff from a given land use category occurs during wet weather periods and can be
described in one of the following ways:
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Exponential Washoff: The washoff load (W) in units of mass per hour is proportional to the
product of runoff raised to some power and to the amount of buildup remaining,
where C; = washoff coefficient, C2 = washoff exponent, q = runoff rate per unit area (inches/hour
or mm/hour), and B = pollutant buildup in mass units. The buildup here is the total mass (not per
area or curb length) and both buildup and washoff mass units are the same as used to express the
pollutant's concentration (milligrams, micrograms, or counts).

Rating Curve Washoff: The rate of washoff W in mass per second is proportional to the runoff
rate raised to some power,
where C; = washoff coefficient, C2 = washoff exponent, and Q = runoff rate in user-defined flow
units.

Event Mean Concentration: This is a special case of Rating Curve Washoff where the exponent
is  1.0 and the coefficient C; represents the washoff pollutant  concentration in mass  per  liter
(Note:  the conversion  between user-defined  flow  units used for runoff and liters  is handled
internally by SWMM).

Note that in each case buildup is continuously depleted as washoff proceeds, and washoff ceases
when there is no more buildup available.

Washoff loads for a given pollutant  and land use category can be reduced by  a fixed percentage
by specifying a  BMP Removal Efficiency that reflects the effectiveness of  any BMP controls
associated with the land use. It is also possible to use the Event Mean Concentration option by
itself, without having to model any pollutant buildup at all.

Street Sweeping

Street sweeping  can be used on each land use category to periodically reduce the accumulated
buildup of specific pollutants. The parameters that describe street sweeping include:
    •  days between sweeping

    •  days since the last sweeping  at the start of the simulation
    •  the fraction of buildup of all  pollutants that is available for removal by  sweeping
    •  the fraction of available buildup for each pollutant removed by sweeping
Note that these parameters can be different for each land use, and the last parameter can vary also
with pollutant.


3.3.10 Treatment

Removal of pollutants  from  the flow streams  entering any drainage system node is modeled by
assigning a set of treatment functions to the node. A treatment function can be any well-formed
mathematical expression involving:
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    •   the pollutant concentration of the mixture of all flow streams entering the node (use the
       pollutant name to represent a concentration)
    •   the removals of other pollutants (use R_ prefixed to the pollutant name to represent
       removal)
    •   any of the following process variables:
       - FLOW for flow rate into node  (in user-defined flow units)
       - DEPTH for water depth above node invert (ft or m)
       - AREA for node surface area (ft2 or m2)
       - DT for routing time step (sec)
       - HRT for hydraulic residence time (hours)
The result of the treatment function can be either a concentration (denoted by the letter C) or a
fractional removal (denoted by R). For example, a first-order decay expression for BOD  exiting
from a storage node might be expressed as:
    C =  BOD * exp(-0.05*HRT)
or the  removal  of some trace pollutant that is proportional to the removal of total  suspended
solids (TSS) could be expressed as:
    R  =  0.75*R TSS
3.3.11 Curves
Curve objects  are  used to describe  a functional  relationship  between  two quantities.  The
following types of curves are available in SWMM:
    •   Storage - describes how the surface area of a Storage Unit node varies with water depth.
    •   Shape - describes how the width of a customized cross-sectional shape varies with height
       for a Conduit link.
    •   Diversion - relates diverted outflow to total inflow for a Flow Divider node.
    •   Tidal - describes how the stage at an Outfall node changes by hour of the day.
    •   Pump - relates flow through a Pump link to the depth or volume at the upstream node or
       to the head delivered by the pump.
    •   Rating - relates flow through an Outlet link to the head difference across the outlet.
    •   Control - determines how the control setting of a pump or flow regulator varies  as a
       function of some control variable (such as water level at a particular node) as specified in
       a Modulated Control rule.
Each curve must be  given a unique name and can be assigned any number of data pairs.

3.3.12 Time Series
Time  Series objects are used to describe how certain object properties vary with time. Time series
can be used to describe:
    •   temperature data
                                           52

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    •  evaporation data

    •  rainfall data
    •  water stage at outfall nodes

    •  external inflow hydrographs at drainage system nodes

    •  external inflow pollutographs at drainage system nodes

    •  control settings for pumps and flow regulators..

Each time series must be given a unique name and can be assigned any number of time-value data
pairs. Time can be specified either as hours from the start of a simulation or as an absolute date
and time-of-day. Time series data can either be entered  directly into the program or be accessed
from a user-supplied Time Series file.

 !'T"'
 W    For  rainfall  time  series, it is only necessary to enter  periods  with  non-zero rainfall
       amounts.  SWMM  interprets  the  rainfall  value as a constant value lasting  over the
       recording interval specified for the rain gage that utilizes the time series. For all other
       types of time series,  SWMM uses interpolation to estimate values at times that fall in
       between the recorded values.

 "'T'1
 v    For times that fall outside the range of the time  series, SWMM will use a value of 0 for
       rainfall and  external inflow time  series,  and either the  first or last  series value for
       temperature, evaporation, and water stage time series.


3.3.13 Time Patterns

Time Patterns  allow  external Dry Weather Flow (DWF)  to vary in a periodic  fashion. They
consist of a set of adjustment factors applied as multipliers to a baseline DWF flow rate or
pollutant concentration. The different types of time patterns include:
    Monthly   - one multiplier for each month of the year
    Daily      - one multiplier for each day of the week

    Hourly     - one multiplier for each hour from 12 AM to 11 PM

    Weekend  - hourly multipliers for weekend days
Each Time Pattern must have a unique name and there is no limit on the number of patterns that
can be created. Each dry  weather inflow  (either flow or quality) can  have up to four patterns
associated with it, one for each type listed above.


3.3.14 LID  Controls


LID Controls are  low impact development  practices designed to capture  surface  runoff and
provide some  combination of detention, infiltration, and  evapotranspiration  to  it. They are
considered as properties of a given subcatchment, similar to how Aquifers and Snow Packs are
treated. SWMM can explicitly model five different generic types of LID controls:
                                            53

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•   Bio-retention Cells  are  depressions that contain vegetation grown in an  engineered  soil
    mixture placed  above  a gravel drainage  bed. They provide  storage,  infiltration  and
    evaporation of both direct rainfall and runoff captured from surrounding areas. Rain gardens,
    street planters, and green roofs are all variations of bio-retention cells.
•   Infiltration Trenches are narrow ditches filled with gravel that intercept runoff from upslope
    impervious areas. They provide  storage  volume  and  additional time for captured runoff to
    infiltrate the native soil below.
•   Continuous Porous Pavement systems are excavated areas filled with gravel and paved over
    with a porous concrete or asphalt mix. Normally all rainfall will immediately pass through the
    pavement into the gravel storage  layer below it where it can infiltrate at natural rates into the
    site's native soil. Block Paver systems consist of impervious paver blocks placed on a sand or
    pea gravel bed with a gravel storage layer below. Rainfall is captured in the open spaces
    between the blocks and conveyed to the storage zone and native soil below.
•   Rain Barrels (or Cisterns) are containers  that collect roof runoff during storm events and can
    either release or re-use the rainwater during dry periods.

•   Vegetative Swales are  channels or depressed areas with sloping sides covered with grass and
    other vegetation.  They slow down the conveyance of collected runoff and allow it more time
    to infiltrate the native soil beneath it.
Bio-retention cells, infiltration trenches, and porous pavement systems can all contain optional
underdrain systems in their gravel  storage beds to convey captured runoff off of the site  rather
than letting it  all infiltrate. They can also have an impermeable floor or liner that prevents any
infiltration into the native soil from occurring. Infiltration trenches and porous pavement systems
can also be subjected to a decrease in hydraulic conductivity over time due to clogging. Although
some LID practices can also  provide  significant pollutant reduction benefits, at this time SWMM
only models their hydrologic performance.
There are two different approaches for placing LID controls within a subcatchment:
•   place one or more controls in an existing subcatchment that will displace an equal amount of
    non-LID area from the subcatchment
•   create a new subcatchment devoted entirely to just a single LID practice.
The first approach allows a mix of LIDs to be placed into  a subcatchment,  each treating a
different portion of the runoff generated  from the non-LID fraction of the subcatchment. Note
that under this option the subcatchment's LIDs act in parallel — it is not possible to make them act
in series (i.e., have the outflow from one  LID control become the inflow to another LID). Also,
after LID placement the subcatchment's Percent Impervious and Width properties may require
adjustment to  compensate for the amount of original subcatchment area that has  now been
replaced by LIDs (see Figure 3-5 below). For example, suppose that a subcatchment which is
40% impervious has 75% of that area converted to  a porous pavement LID. After the LID is
added the subcatchment's percent imperviousness should be changed to the percent of impervious
area remaining divided by the percent of non-LID area remaining. This works out to (1 - 0.75)*40
/ (100-0.75*40) or 14.3%.
                                            54

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                                Ai hi,
                                                                    Wi.lth
     Befoie LIDs


                                  After LIDs

Figure 3-5. Adjustment of subcatchment parameters after LID placement.



3.4    Computational Methods

SWMM  is  a physically  based,  discrete-time simulation model.  It  employs  principles  of
conservation  of mass, energy, and momentum  wherever  appropriate.  This section  briefly
describes the methods SWMM uses to model stormwater runoff quantity and quality through the
following physical processes:
       •   Surface Runoff                          •   Infiltration
       •   Groundwater                            •   Snowmelt
       •   Flow Routing                            •   Surface Ponding
       •   Water Quality Routing


3.4.1   Surface Runoff

The conceptual view of surface runoff used by SWMM is illustrated in Figure 3-5 below. Each
subcatchment surface is treated as a nonlinear reservoir. Inflow comes from precipitation and any
designated  upstream  subcatchments.  There  are  several  outflows,  including  infiltration,
evaporation, and surface runoff. The capacity of this "reservoir" is  the maximum depression
storage, which is  the maximum surface storage provided by ponding,  surface wetting,  and
interception. Surface runoff per unit area, Q,  occurs  only when the  depth of water in the
"reservoir"  exceeds the maximum depression storage, dp, in which case the outflow is given by
Manning's equation. Depth of water over the  subcatchment (d in feet) is  continuously updated
with time (t in  seconds) by solving numerically a water balance equation over the subcatchment.
                                           55

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                                       RAINFALL,
                  EVAPORATION  SNOtyMELT
                                 OfO.
                             — -rl— •!*•——-———.— — —
                                   INFILTRATION

                     Figure 3-6. Conceptual view of surface runoff.
3.4.2  Infiltration

Infiltration is the process of rainfall penetrating the ground surface into the unsaturated soil zone
of pervious subcatchments areas. SWMM offers three choices for modeling infiltration:

Horton's Equation
This method is based on empirical observations showing that infiltration decreases exponentially
from an initial maximum rate to some minimum rate over  the course of a long rainfall event.
Input parameters required by this method include  the maximum and minimum infiltration rates, a
decay coefficient that describes how fast the rate  decreases over time, and a time it takes a fully
saturated soil to completely dry.

Green-Ampt Method
This method for modeling infiltration assumes that a sharp wetting front exists in the soil column,
separating soil with some initial moisture content below from saturated soil above. The input
parameters required are the initial moisture deficit of the soil, the soil's hydraulic conductivity,
and the suction head at the wetting front.

Curve Number Method
This approach is adopted from the NRCS (SCS) Curve Number method  for estimating runoff. It
assumes that the total infiltration capacity of a soil can be found from the soil's tabulated Curve
Number.  During a rain event this capacity  is depleted as a  function of cumulative rainfall and
remaining capacity.  The input parameters for this method are  the curve number and the time it
takes a fully saturated soil to completely dry.

SWMM also allows the infiltration recovery rate  to be adjusted by a fixed amount on a monthly
basis to account for seasonal variation in  such  factors as  evaporation rates and groundwater
levels. This optional monthly soil recovery pattern is  specified as  part of a project's Evaporation
data.
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3.4.3  Groundwater
Figure 3-6 is a definitional sketch of the two-zone groundwater model that is used in SWMM.
The upper zone is unsaturated with a variable moisture content of 6.  The lower zone is fully
saturated and therefore its moisture content is fixed at the soil porosity (|). The fluxes shown in the
figure, expressed as volume per unit area per unit time, consist of the following:
                   f
f,
                           ELI
f
                                  EL
                                                                    TOT
                       Figure 3-7. Two-zone groundwater model.

fi   infiltration from the surface

fEu evapotranspiration from the upper zone which is a fixed fraction of the un-used surface
    evaporation
fu  percolation from the upper to lower zone which depends on the upper zone moisture content
    6 and depth du

fEL evapotranspiration from the lower zone, which is a function of the depth of the upper zone du
fL  percolation from the lower zone to deep groundwater which depends on the lower zone depth
    dL
fG  lateral groundwater interflow to the drainage system, which depends on the lower zone depth
    dL as well as the depth in the receiving channel or node.

After computing the water fluxes that exist during a given time step, a  mass  balance is written for
the change in water volume stored in each zone so that a new water table depth and unsaturated
zone moisture content can be computed for the next time step.


3.4.4  Snowmelt

The snowmelt routine in SWMM is a part of the runoff modeling process. It updates the state of
the snow packs associated with each  subcatchment by accounting for snow accumulation, snow
redistribution by areal depletion and  removal operations, and  snow  melt via heat budget
accounting. Any snowmelt coming off the pack is treated as an additional rainfall input onto the
subcatchment.

At each runoff time step the following computations are made:
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    l.  Air temperature and melt coefficients are updated according to the calendar date.
    2.  Any precipitation that falls as snow is added to the snow pack.
    3.  Any excess snow depth on the plowable area of the pack is redistributed according to the
       removal parameters established for the pack.
    4.  Areal coverages of snow on the impervious and pervious areas of the pack are reduced
       according to the Areal Depletion Curves defined for the study area.
    5.  The amount of snow in the pack that melts to liquid water is found using:
           a.   a heat budget equation for periods with rainfall, where melt rate increases  with
               increasing air temperature, wind speed, and rainfall intensity
           b.   a degree-day equation for periods with no rainfall,  where melt rate equals the
               product of a melt coefficient and the difference between the air temperature and
               the pack's base melt temperature.
    6.  If no melting occurs, the pack temperature is adjusted up or down based on the product of
       the difference between current and past air temperatures and an adjusted melt coefficient.
       If melting occurs, the temperature of the pack is increased by the equivalent heat content
       of the melted snow, up to the base melt temperature. Any remaining melt liquid beyond
       this is available to runoff from the pack.
    7.  The available snowmelt  is then reduced  by the  amount of free water holding capacity
       remaining  in the  pack. The remaining melt is treated the same as an additional rainfall
       input onto the subcatchment.


3.4.5  Flow Routing

Flow routing within a conduit link in SWMM  is  governed  by the conservation of mass and
momentum equations for gradually varied, unsteady flow (i.e., the Saint Venant flow equations).
The SWMM user has a choice on the level of sophistication used to solve these equations:
    •  Steady Flow Routing
    •  Kinematic Wave Routing
    •  Dynamic Wave Routing

Steady Flow Routing

Steady Flow routing represents the simplest type of routing possible (actually no routing) by
assuming that within each computational time step flow is uniform and steady. Thus it  simply
translates inflow hydrographs at the upstream end of the conduit to the downstream end, with no
delay or change in shape. The normal flow equation is used to relate flow rate to flow area (or
depth).

This type of routing cannot account for channel storage, backwater effects,  entrance/exit losses,
flow reversal or pressurized flow. It can only be used with dendritic conveyance networks, where
each node has only a single outflow link (unless the node is a  divider in which case  two outflow
links are required). This form of routing is insensitive to the time step employed and is really only
appropriate for preliminary analysis using long-term continuous simulations.
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Kinematic Wave Routing

This routing method solves the continuity  equation  along  with a  simplified  form  of the
momentum equation in each conduit. The latter requires that the slope of the water surface equal
the slope of the conduit.

The maximum flow that can be conveyed through a conduit is the full normal flow value. Any
flow in excess of this entering the inlet node is either lost from the system or can pond atop the
inlet node and be re-introduced into the conduit as capacity becomes available.

Kinematic wave routing allows flow and area to  vary both spatially and temporally within  a
conduit.  This  can result in attenuated and delayed outflow hydrographs as inflow is  routed
through the channel.  However this  form  of routing  cannot account for  backwater  effects,
entrance/exit losses, flow reversal, or pressurized flow, and is also restricted to dendritic network
layouts. It can usually maintain numerical stability with moderately large time steps, on the order
of 5 to  15 minutes. If the  aforementioned  effects are not  expected to be significant then this
alternative can be an accurate and efficient routing method, especially for long-term simulations.

Dynamic Wave Routing

Dynamic Wave routing solves the complete one-dimensional Saint Venant flow equations and
therefore produces the most theoretically  accurate results. These  equations consist  of the
continuity and momentum equations for conduits and a volume continuity equation at nodes.

With this form of routing  it is possible to represent pressurized flow  when a closed  conduit
becomes full, such that flows can exceed the full normal flow value. Flooding occurs when the
water depth at a node exceeds the maximum available depth, and the excess flow is either lost
from the system or can pond atop the node and  re-enter the drainage system.

Dynamic wave routing can account for channel storage, backwater, entrance/exit losses, flow
reversal,  and pressurized flow. Because it couples  together  the solution for both water levels at
nodes and flow in conduits it can be applied to  any general network layout, even those containing
multiple downstream diversions and loops.  It  is the  method of choice for systems subjected to
significant backwater effects due to downstream flow restrictions and with flow regulation via
weirs and orifices. This generality comes at a price of having to use much smaller time steps, on
the order of a minute or less (SWMM will automatically reduce the user-defined maximum time
step as needed to maintain numerical stability).
Each of these routing methods employs the Manning equation to relate  flow rate to flow depth
and bed (or friction) slope.  The one exception is for circular Force Main shapes under pressurized
flow, where  either the Hazen-Williams or Darcy-Weisbach equation is used instead.


3.4.6  Surface Ponding

Normally in flow routing,  when the flow into a junction exceeds the capacity of the system to
transport it further downstream, the excess volume overflows the system and is lost. An option
exists to have instead the excess volume be stored atop the junction, in a ponded fashion,  and be
reintroduced into the system as  capacity  permits.  Under  Steady and Kinematic Wave flow
routing, the  ponded water is stored simply  as an  excess volume. For  Dynamic Wave routing,
which is influenced by the  water depths maintained at nodes, the excess volume is assumed to
                                           59

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pond  over the  node with a  constant surface area. This  amount of surface area is  an input
parameter supplied for the junction.

Alternatively, the user may wish to represent the  surface overflow system explicitly. In open
channel systems this can include road overflows at bridges  or culvert crossings  as well  as
additional  floodplain storage areas. In  closed  conduit  systems,  surface  overflows may  be
conveyed  down streets, alleys, or other surface routes to the next available stormwater inlet or
open channel.  Overflows may also be impounded  in surface depressions such as parking lots,
back yards or other areas.


3.4.7  Water Quality Routing

Water  quality routing within  conduit links assumes that the conduit behaves as a continuously
stirred tank reactor (CSTR). Although a plug flow reactor assumption might be more realistic, the
differences will be small if the travel time through the conduit is on the same order as the routing
time step.  The concentration of a constituent exiting the conduit at the end of a time step is found
by integrating the conservation of mass equation, using average values for quantities that might
change over the time step such as flow rate and conduit volume.

Water  quality modeling within storage unit nodes follows the same approach used for conduits.
For other types of nodes that have no volume, the quality of water exiting the node is simply the
mixture concentration of all water entering the node.


3.4.8  LID Representation

LID controls are represented by a combination of vertical layers whose properties are defined  on
a per-unit-area basis. This allows LIDs of the same design but differing areal coverage to easily
be placed within different subcatchments of a study area. During a simulation SWMM performs a
moisture balance that keeps track of how much water moves between and is stored within each
LID layer. As  an example, the layers used to model a bio-retention  cell and the flow pathways
between them are shown in Figure 3-8. The various possible layers consist of the following:
            Rainfall   ET
Overflow           t f
                                                          Runon
1 	
±3
Surface Layer/'
Soil Layer '
Infiltratic
•
f
Percolat
n
Storage Layer
                                                           on
                        Underdrain
                                                   Infiltration
                 Figure 3-8. Conceptual diagram of a bio-retention cell LID.
                                           60

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•   The Surface Layer corresponds to  the ground (or pavement) surface that receives direct
    rainfall and runon from upstream land areas, stores excess inflow in depression storage, and
    generates surface outflow that either enters the drainage  system or flows onto downstream
    land areas.
•   The Pavement Layer is  the layer of porous concrete or asphalt used  in continuous porous
    pavement systems,  or is the paver blocks and filler material used in modular systems.
•   The Soil Layer is the engineered soil mixture used in bio-retention cells to support vegetative
    growth.

•   The Storage Layer is a bed of crushed rock or gravel that provides storage in bio-retention
    cells, porous pavement,  and intfiltration trench systems.  For a rain barrel it is simply the
    barrel itself.
•   The Underdraw System  conveys water out of the gravel storage layer of bio-retention cells,
    porous  pavement systems,  and infiltration  trenches (typically with  slotted pipes) into a
    common outlet pipe or chamber. For rain barrels it is simply the drain valve at the bottom of
    the barrel.
Table 3-1 indicates which combination of layers applies to each type of LID (x means required, o
means optional).

                 Table 3-1. Layers used to model different types of LID units.
LID Type
Bio-Retention Cell
Porous Pavement
Infiltration Trench
Rain Barrel
Vegetative Swale
Surface
X
X
X

X
Pavement

X



Soil
X




Storage
X
X
X
X

Underdrain
0
o
0
X

All of the LID controls provide some amount of rainfall/runoff storage and evaporation of stored
water (except for rain barrels). Infiltration into native soil occurs in vegetative swales and can
also occur in bio-retention cells, porous pavement systems, and infiltration trenches if those
systems do not employ an optional impermeable bottom liner. Infiltration trenches and porous
pavement systems can also be subjected to clogging.  This reduces their hydraulic conductivity
over time proportional to the cumulative hydraulic loading on the trench or pavement.

The performance  of the LID controls placed in a subcatchment is reflected in the overall runoff,
infiltration,  and evaporation  rates  computed  for the  subcatchment  as  normally reported  by
SWMM. SWMM's Status Report also contains a section entitled LID Performance Summary that
provides an  overall  water balance for each LID control  placed in each subcatchment. The
components of this water  balance include total inflow, infiltration, evpaoration, surface runoff,
underdrain flow and initial and final stored volumes,  all expressed as inches (or mm) over the
LID's area. Optionally, the entire time series of flux rates and moisture levels for a selected LID
control in a given subcatchment can be written to a tab delimited text file for easy viewing and
graphing in a spreadsheet program (such as Microsoft Excel).
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CHAPTER 4 - SWMM'S MAIN WINDOW
This chapter discusses the essential features ofSWMM's workspace. It describes the main menu
bar, the tool and status bars, and the three windows used most often - the Study Area Map, the
Browser, and the Property Editor. It also shows how to set program preferences.
4.1
Overview
The EPA SWMM main window is pictured below. It consists of the following user interface
elements: a Main Menu, several Toolbars, a Status Bar, the Study Area Map window, a Browser
panel, and a Property Editor window. A description of each of these elements is provided in the
sections that follow.
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4.2    Main Menu

The Main Menu located across the top of the EPA SWMM main window contains a collection of
menus used to control the program. These include:
    •   File Menu
    •   Edit Menu
    •   View Menu
    •   Project Menu
    •   Report Menu
    •   Tools Menu
    •   Window Menu
    •   Help Menu

File Menu

The File Menu contains commands for opening and saving data files and for printing:
    Combine
    Page Setup
    Print Preview

    Print
    Exit
Description
Creates a new SWMM project
Opens an existing project
Reopens a recently used project
Saves the current project
Saves the current project under a different name
Exports study area map to a file in a variety of formats;
Exports current results to a Hot Start file
Combines two Routing Interface files together
Sets page margins and orientation for printing
Previews a printout of the currently active view (map, report,
graph, or table)
Prints the current view
Exits EPA SWMM
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Edit Menu

The Edit Menu contains commands for editing and copying:

    Command        Description
    Copy To          Copies the currently active view (map, report, graph or table)
                     to the clipboard or to a file
    Select Object      Enables the user to select an object on the map
    Select Vertex      Enables the user to select the vertex of a subcatchment or link
    Select Region     Enables the user to delineate a region on the map for selecting
                     multiple objects
    Select All         Selects all objects when the map is the active window or all
                     cells of a table when a tabular report is the active window
    Find Object       Locates a specific object by name on the map
    Find Text         Locates specific text in a Status Report
    Group Edit        Edits a property for the group of objects that fall within the
                     outlined region of the map
    Group Delete      Deletes a group of objects that fall within the outlined region
                     of the map

View Menu

The View Menu contains commands for viewing the Study Area Map:

    Command         Description
    Dimensions        Sets reference coordinates and distance units for the study
                      area map
    Backdrop          Allows a backdrop image to be added, positioned, and
                      viewed
    Pan               Pans across the map
    Zoom In           Zooms in on the map
    Zoom Out         Zooms out on the map
    Full Extent         Redraws the map at full extent
    Query             Highlights objects on the map that meet specific criteria
    Overview          Toggles the display of the Overview Map
    Objects            Toggles display of classes of objects on the map
    Legends           Controls display of the map legends
    Toolbars           Toggles display of tool bars
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Project Menu
The Project menu contains commands related to the current project being analyzed:
    Command
    Summary
    Details
    Defaults
    Calibration Data
    Run Simulation
Description
Lists the number of each type of object in the project
Shows a detailed listing of all project data
Edits a project's default properties
Registers files containing calibration data with the project
Runs a simulation
Report Menu
The Report menu contains commands used to report analysis results in different formats:
    Command
    Status
    Graph
    Table
    Statistics
    Customize
Description
Displays a status report for the most recent simulation run
Displays simulation results in graphical form
Displays simulation results in tabular form
Displays a statistical analysis of simulation results
Customizes the display style of the currently active graph
Tools Menu
The Tools menu contains commands used to configure program preferences, study area map
display options, and external add-in tools:
    Command
    Program
    Preferences
    Map Display
    Options
    Configure Tools
Description
Sets program preferences, such as font size, confirm
deletions, number of decimal places displayed, etc.
Sets appearance options for the Map, such as object size,
annotation, flow direction arrows, and back-ground color
Adds, deletes, or modifies add-in tools
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Window Menu

The Window Menu contains commands for arranging and selecting windows within the SWMM
workspace:

    Command          Description
    Cascade            Arranges windows in cascaded style, with the study area
                       map filling the entire display area
    Tile                Minimizes the study area map  and tiles the remaining
                       windows vertically in the display area
    Close All           Closes all open windows except for the study area map
    Window List        Lists all open windows; the currently selected window has
                       the focus and is denoted with a check mark
Help Menu

The Help Menu contains commands for getting help in using EPA SWMM:

    Command           Description
    Help Topics          Displays the Help system's Table of Contents
    How Do I            Displays a list of topics covering the most common
                        operations
    Measurement Units   Shows measurement units for all of SWMM's parameters
    Error Messages       Lists the meaning of all error messages
    Tutorial             Presents a short tutorial introducing the user to EPA
                        SWMM
    About               Lists information about the version of EPA SWMM being
                        used
4.3    Toolbars

Toolbars provide shortcuts to commonly used operations. There are three such toolbars:
    •   Standard Toolbar
    •   Map Toolbar

    •   Object Toolbar

All toolbars can be docked underneath the  Main Menu bar, docked on the right side of the
Browser Panel or dragged to any location on the EPA SWMM workspace. When undocked, they
can also be re-sized.

Toolbars can be made visible or invisible by selecting View » Toolbars from the Main Menu.
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Standard Toolbar
The Standard Toolbar contains buttons for the following commonly used commands:
    D     Creates a new project (File » New)
   C&    Opens an existing project (File » Open)
   Q|    Saves the current project (File » Save)
   Q    Prints the currently active window (File » Print)
   IRl    Copies selection to the clipboard or to a file (Edit » Copy To)
   M    Finds a specific object on the Study Area Map (Edit » Find Object) or
          specific text in the Status Report (Edit » Find Text)
    ^     Runs a simulation (Project » Run Simulation)
   ? ij    Makes a visual query of the study area map (View » Query)
   ttj    Creates a profile plot of simulation results (Report » Graph » Profile)
    fel    Creates a time series plot of simulation results (Report » Graph » Time
          Series)
   l£_    Creates a scatter plot of simulation results (Report» Graph » Scatter)
   iH    Creates a table of simulation results (Report » Table)
    2     Performs a statistical analysis of simulation results  (Report » Statistics)
   iS*    Modifies display options for the currently active view (Tools » Map
          Display Options or Report » Customize)
   ?H]    Arranges windows in cascaded style, with the study area map filling the
          entire display area (Window » Cascade)
Map Toolbar
The Map Toolbar contains the following buttons for viewing the study area map:
    ^     Selects an object on the map (Edit » Select Object)
    l>    Selects link or subcatchment vertex points (Edit» Select Vertex)
   S    Selects a region on the map (Edit » Select Region)
   *f*    Pans across the map (View » Pan)
   (t^    Zooms in on the map (View » Zoom In)
   
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Object Toolbar
The Object Toolbar contains buttons for adding objects to the study area map:
    ^j?    Adds a rain gage to the map
    fl!    Adds a subcatchment to the map
    O    Adds a junction node to the map
    V    Adds an outfall node to the map
    -0    Adds a flow divider node to the map
    bd    Adds a storage unit node to the map
    !—'    Adds a conduit link to the map
    G3    Adds a pump link to the map
    S    Adds an orifice link to the map
    Q    Adds a weir link to the map
    ®    Adds an outlet link to the map
    T    Adds a label to the map

4.4    Status Bar
The Status Bar appears at the bottom of SWMM's Main Window and is divided into six sections:
 Auto-Length: Off  -  Offsets: Depth  -   Flow Units: CFS  »  Q   Zoom Level: 10(K   X,Y: 711.500,7.584 ft
Auto-Length
Indicates whether the automatic computation of conduit lengths and subcatchment areas is turned
on or off. The setting can be changed by clicking the drop down arrow.
Offsets
Indicates whether the positions of links above the invert of their connecting nodes are expressed
as a Depth above the node invert or as the Elevation of the offset. Click the drop down arrow to
change this option. If changed, a dialog box will appear asking if all existing offsets in the current
project should be changed or not (i.e., convert Depth offsets to Elevation offsets or Elevation
offsets to Depth offsets, depending on the option selected)
Flow Units
Displays the current flow units that are in effect. Click the drop down arrow to change the choice
of flow units. Selecting a US flow unit  means that all other quantities will be expressed in US
units, while choosing a metric flow unit will force all quantities to be expressed in metric units.
The units of previously entered data are not automatically adjusted if the unit system is changed.
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Run Status
A faucet icon shows:
    •   no running water if simulation results are not available,
    •   running water when simulation results are available,
    •   a broken faucet when simulation results are available but may be invalid because project
        data have been modified.

Zoom Level
Displays the current zoom level for the map (100% is full-scale).

XY Location
Displays the map coordinates of the current position of the mouse pointer.
4.5    Study Area Map

The  Study Area Map (shown below)  provides  a planar schematic diagram of the objects
comprising a drainage system. Its pertinent features are as follows:
                            A Study Area Map
| x|
       The location of objects and the distances between them do not necessarily have to
       conform to their actual physical scale.
       Selected properties of these objects, such as water quality at nodes or flow velocity in
       links, can be displayed by using different colors. The color-coding is described in a
       Legend, which can be edited.
       New objects can be directly added to the map and existing objects can be selected for
       editing, deleting, and repositioning.

       A backdrop drawing (such as a street or topographic map) can be placed behind the
       network map for reference.
       The map can be zoomed to any scale and panned from one position to another.
       Nodes and links can be drawn at different sizes, flow direction arrows added, and object
       symbols, ID labels and numerical property values displayed.
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       The map can be printed, copied onto the Windows clipboard, or exported as a DXF file or
       Windows metafile.
4.6    Data Browser
The  Data Browser panel (shown below) appears when the Data tab on the left panel of the
SWMM workspace is selected. It provides access to  all of the data objects in a project. The
vertical sizes of the list boxes in the browser can be adjusted by using the splitter bar located just
below  the upper list box.  The width of the  Data Browser panel can be adjusted by using the
splitter bar located along its right edge.
 Data
        Map
  i±i Hydrology
  id Hydraulics
     ffl Nodes
     Q Links
           Conduits
           Pumps
           Orifices
           Weirs   v
O  -0

Conduits
 11
 12
                  v
                        The upper list box displays the various categories of data
                        objects available to a SWMM project. The lower list box
                        lists the name of each individual  object of the currently
                        selected data category.

                        The buttons between the two list boxes of the Data Browser
                        are used as follows:
                        *  adds a new object
                         1  deletes the selected object
                        & edits the selected object
                           moves the selected object up one position
                           moves the selected object down one position
Cc
o
A
Z
                           T  sorts the objects in ascending order
                        Selections made in the Data Browser are coordinated with
                        objects highlighted on the Study Area Map, and vice versa.
                        For example, selecting a conduit in the Data Browser will
                        cause  that conduit to  be  highlighted on  the  map, while
                        selecting it on the map will cause it to become the selected
                        object in the Data Browser.
4.7     Map Browser

The  Map Browser panel (shown below) appears when the Map tab  on the left panel  of the
SWMM workspace is selected. It controls the mapping themes and time periods viewed  on the
Study Area Map. The width of the Map Browser panel can  be adjusted by using the splitter bar
located along its right edge.
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 Data   Map          The Map Browser consists of the following three panels that control what
                    results are displayed on the map:

                    The Themes panel selects a set of variables to view in color-coded fashion
   Area        v        ,   AT
                    on the Map.
  Nodes
   invert        %      The Time Period panel selects which time period of the simulation results
                    are viewed on the Map.
  Links                                 r

       ep           The Animator panel controls the animated display of the  Study Area Map
                    and all Profile Plots over time.
  TirneFeiiod
  Date              The width of the Map Browser panel can be adjusted by using the  splitter
   01/01/199          bar located along its right edge.
The Themes panel of the Map Browser is used to select a thematic variable to view in color-
coded fashion on the Study Area Map.
 Subcatchments       Subcatchments - selects the theme to display for the subcatchment areas
            v       shown on the Map.
 Nodes              Nodes - selects the theme to display for the drainage system nodes shown
  Invert      v       on the Map.

 fr'n*s.               Links - selects the theme to display for the drainage system links shown on
  Max, Depth  *»*       the Map.
The Time Period panel of the Map Browser allows is used to select a time period in which to
view computed results in thematic fashion on the Study Area Map.

 I irne Pf-nod
 Date               Date - selects the day for which simulation results will be viewed.
  01/01/1998 v
 Time of Day          Time of Day - selects the hour of the current day for which simulation
  03:00:00    v       results will be viewed.
  <    •     >

   apse   Ime         Elapsed Time - selects the elapsed time from the start of the simulation for
  0.03:00:00  *       which results will be viewed.
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The Animator panel of the Map Browser contains controls for animating the Study Area Map and
all Profile Plots through  time i.e.,  updating map color-coding and hydraulic grade line profile
depths as the simulation time clock is automatically moved forward or back. The meaning of the
control buttons are as follows:
 Animator
  K  <

H Returns to the starting period.
 ^ Starts animating backwards in time
H Stops the animation
 ^ Starts animating forwards in time
The slider bar is used to adjust the animation speed.
4.8    Property Editor

The Property Editor (shown to the right) is used to edit
the properties of data objects that can  appear on the
Study Area Map. It  is invoked when one  of  these
objects is selected (either on the Study Area Map or in
the Data Browser) and double-clicked or when the Data
Browser's Edit button "3 is clicked.

Key features of the Property Editor include:
    •   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.
•t.
Property
Inlet Node
Outlet Node
Description
Tag
Shape
Length
Roughness
Inlet Offset
Value
17
18


[aRCULAR'Ti]
400
0.01
0
/t
v
Click to edit the conduit's cross
section geometry
       A hint area is displayed at the bottom of the Editor with an expanded description of the
       property being edited. The size of this area can be adjusted by dragging the splitter bar
       located just above it.
       The Editor window can be moved and re-sized via the normal Windows operations.
       Depending on the property, the value field can be one of the following:
       o  a text box in which you enter a value

       o  a dropdown combo box from which you select a value from a list of choices
       o  a dropdown combo box in which you can enter a value or select from a list of choices
       o  an ellipsis button which you click to bring up a specialized editor.

       The property field in the Editor that currently has the focus will be highlighted with a
       white background.
       Both the mouse and the Up and Down arrow keys on the keyboard can be used to move
       between property fields.
       To begin editing the property with the focus, either begin typing a value or hit the Enter
       key.
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       To have the program accept edits made in a property field, either press the Enter key or
       move to another property. To cancel the edits, press the Esc key.

       The Property Editor can be hidden by clicking the button in the upper right corner of its
       title bar.
4.9    Setting Program Preferences

Program  preferences allow  one  to  customize  certain program features.  To  set  program
preferences, select Program Preferences from the Tools menu. A Preferences dialog form will
appear containing two tabbed pages - one for General Preferences and one for Number Formats.
General Preferences Number Formats |











DBoldFonls
Large Fonts
v Blinking Map Highlighter
V Flyover Map Labeling
v' Confirm Deletions
Automatic Backup File
y' Report Elapsed Time by Default
v> Prompt to Save Results
Clear File List
"emporary Directory
s










1
I    OK
                                          Cancel
Help
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General Preferences

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


       Flyover Map Labeling



       Confirm Deletions

       Automatic Backup File
       Report Elapsed Time by
       Default
       Prompt to Save Results
       Clear File List
       Temporary Directory
Description

Check to use bold fonts in all windows
Check to use large size fonts in all windows
Check to make the selected object on the study area
map blink on and off
Check to display the ID  label and  current theme
value in a hint-style box whenever the  mouse  is
placed over an object on the study area map
Check to display a confirmation dialog box before
deleting any object
Check to save a backup copy of a  newly opened
project to disk named with a .bak extension

Check to use elapsed time (rather than date/time) as
the default for  time series graphs and tables.
If left  unchecked  then   simulation  results are
automatically saved to disk when the current project
is closed. Otherwise the user will be asked if results
should be saved.
Check to clear the list of most recently used files
that appears when File » Reopen is selected from
the Main Menu
Name of the directory (folder) where EPA SWMM
writesitstemporaryfiles
 W    The Temporary Directory must be a file directory (folder) where the user has write
       privileges and must have sufficient space to temporarily store files which can easily grow
       to several tens of megabytes for larger study areas and  simulation runs. The original
       default is the folder where Windows writes its temporary files.


Number Format Preferences

The Number Formats page of  the Preferences  dialog controls the number of decimal places
displayed when simulation results  are reported. Use the dropdown list boxes to select a specific
Subcatchment, Node or Link parameter, and then use the edit boxes next  to them to select the
number of decimal places to use when displaying computed results for the parameter. Note that
the number of decimal places displayed for any particular input design parameter, such as slope,
diameter, length, etc. is whatever the user enters.
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CHAPTER 5 - WORKING WITH PROJECTS
Project files contain all of the information used to model a study area. They are usually named
with a .INP extension. This section describes how to create, open, and save EPA SWMMprojects
as well as setting their default properties.
5.1    Creating a New Project
To create a new project:
    l.  Select File » New from the Main Menu or click Lj on the Standard Toolbar.
    2.  You will be prompted to save the existing project (if changes were made to it) before the
       new project is created.
    3.  A new, unnamed project is created with all options set to their default values.
A new project is automatically created whenever EPA SWMM first begins.
 ''"!)
 W    If you are going to use a backdrop image with automatic area and length calculation, then
       it is recommended that  you set the map dimensions immediately after creating the new
       project (see Setting the Map's Dimensions).
5.2    Opening an Existing Project
To open an existing project stored on disk:
    1.  Either select File » Open from the Main Menu or click Q*' on the Standard Toolbar.
    2.  You will be prompted to save the current project (if changes were made to it).
    3.  Select the file to open from the Open File dialog form that will appear.
    4.  Click Open to open the selected file.
To open a project that was worked on recently:
    l.  Select File » Reopen from the Main Menu.
    2.  Select a file from the list of recently used files to open.

5.3    Saving a Project
To save a project under its current name either select File » Save from the Main Menu or click
•D on the Standard Toolbar.
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To save a project using a different name:

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


5.4     Setting Project Defaults

Each project has a set of default values that are used unless overridden by the SWMM user. These
values fall into three categories:

    1.   Default ID labels (labels used to identify nodes and links when they are first created)
    2.   Default subcatchment properties (e.g., area, width, slope, etc.)

    3.   Default node/link properties (e.g., node invert, conduit length, routing method).

To set default values  for a project:

    l.   Select Project» Defaults from the Main Menu.

    2.   A Project Defaults dialog will appear with three pages, one for each category listed
        above.

    3.   Check the box in the lower left of the dialog form if you want to save your choices for
        use in all new future projects as well.

    4.   Click OK to accept your choice of defaults.

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


Default ID Labels

The  ID  Labels page  of the Project Defaults dialog form is used to determine how SWMM will
assign default ID labels for the visual project components when they are first created. For each
type of object you can enter a label prefix in the corresponding entry field or leave the field blank
if an object's default name will simply be a number. In the last field you can enter an increment to
be used when  adding a numerical suffix to the default label. As an  example, if C were used as a
prefix for Conduits along with an increment of 5,  then as conduits are created they receive default
names  of C5, CIO,  C15, and so on.  An object's default name can be  changed by using the
Property Editor for visual objects or the object-specific editor for non-visual objects.
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                        Project Defaults
D Labels Subcatchments Nodes/Links
Object ID Prefix
Rain Gages
Subcatchments
Junctions
Outfalls
Storage Units
Conduits
Pumps
Regulators
ID Increment






1

                         H Save as defaults for all new projects
                                         Cancel
Default Subcatchment Properties
The  Subcatchment page of the  Project Defaults dialog sets default property values for newly
created Subcatchments. These properties include:
    •  Subcatchment Area
    •  Characteristic Width
    •  Slope
    •  % Impervious
    •  Impervious Area Roughness
    •  Pervious Area Roughness
    •  Impervious Area Depression Storage
    •  Pervious Area Depression Storage
    •  % of Impervious Area with No Depression Storage
    •  Infiltration Method
The default properties of a Subcatchment can be modified later by using the Property Editor.
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Default Node/Link Properties
The Nodes/Links page of the Project  Defaults dialog sets default property values for newly
created nodes and links. These properties include:
    •   Node Invert Elevation
    •   Node Maximum Depth
    •   Node Ponded Area
    •   Conduit Length
    •   Conduit Shape and Size
    •   Conduit Roughness
    •   Flow Units
    •   Link Offsets Convention
    •   Routing Method
    •   Force Main Equation
The defaults automatically assigned to  individual objects can  be changed by using the object's
Property Editor. The choice of Flow Units and Link Offsets Convention can be changed directly
on the main window's Status Bar.
5.5    Measurement Units
SWMM can use either US units or SI metric units. The choice of flow units determines what unit
system is used for all other quantities:
    •   selecting CFS (cubic feet per second), GPM (gallons per minutes), or MGD (million
       gallons per day) for flow units implies that US units will be used throughout
    •   selecting CMS (cubic meters per second), LPS (liters per second), or MLD (million liters
       per day) as flow units implies that SI units will be used throughout.
Flow units can be selected directly on the main window's Status Bar or by setting a project's
default values.  In the latter case the selection can be saved so that all new  future projects will
automaticall  use those units.
       The units of previously entered data are not automatically adjusted if the unit system is
       changed.
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5.6     Link Offset Conventions
Conduits and flow regulators (orifices, weirs, and outlets) can be offset some distance above the
invert of their connecting end nodes as depicted below:
There are two different conventions available for specifying the location of these offsets. The
Depth convention uses the offset distance from the node's invert (distance between © and (D, in
the figure above). The Elevation convention uses the absolute elevation of the offset location (the
elevation of point © in the figure). The choice of convention can be made on the Status Bar of
SWMM's main window or on the Node/Link  Properties page of the  Project Defaults  dialog.
When this convention is changed, a dialog will appear giving one the option to automatically re-
calculate all existing link offsets in the current project using the newly selected convention
5.7    Calibration Data
SWMM can compare the results of a simulation with measured field data in its Time Series Plots,
which are discussed in section 9.4. Before SWMM can use such calibration data they must be
entered into a specially formatted text file and registered with the project.

Calibration Files
Calibration Files contain measurements of a single parameter at one or more locations that can be
compared with simulated values in Time Series Plots.  Separate files can be used for each  of the
following parameters:
    •  Subcatchment Runoff
    •  Subcatchment Pollutant Washoff
    •  Groundwater Flow
    •  Groundwater Elevation
    •  Snow Pack Depth
    •  Node Depth
    •  Node Lateral Inflow
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    •   Node Flooding
    •   Node Water Quality
    •   Link Flow Rate
The format of the file is described in Section 11.5.

Registering Calibration Data
To register calibration data residing in a Calibration File:
    l.  Select Project» Calibration Data from the Main Menu.
    2.  In the Calibration Data dialog form shown below, click in the box next to the parameter
       (e.g., node depth, link flow, etc.) whose calibration data will be registered.
    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.
Calibration Data | X




Calibration Variable
Subcatchment Runoff
Subcatchment Washoff
Node Water Depth
Name of Calibration File




• CAMy Projects\SWMM5\QA_Report\Extran\extran1.dat
Node Water Quality
Node Lateral Inflow
Node Flooding
Groundwater Flow
Groundwater Elevation
Snow Pack Depth
Link Flow Depth
Link Flow Velocity








Efa Browse ^ Edit OK Cancel Help


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5.8    Viewing All Project Data

A listing of all project data (with the exception of map coordinates) can be viewed in a non-
editable window, formatted for input to SWMM's computational engine. This can be useful for
checking data consistency and to make sure that no key components are missing. To view such a
listing, select Project » Details from the Main Menu. The format of the data in this listing is the
same as that used when the file is saved to disk. It is described in detail in Appendix D.2.
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CHAPTER 6 - WORKING WITH OBJECTS
SWMM uses various types of objects to model a drainage area and its conveyance system. This
section describes how these objects can be created, selected, edited, deleted, and repositioned.
6.1    Types of Objects

SWMM contains both physical objects that can appear on its Study Area Map, and non-physical
objects that encompass  design,  loading, and operational information. These objects, which are
listed in the Data Browser and were described in Chapter 3, consist of the following:

                  Project Title/Notes            Nodes
                  Simulation Options           Links
                  Climatology                 Transects
                  Rain Gages                   Control Rules
                  Subcatchments               Pollutants
                  Aquifers                     Land Uses
                  Snow Packs                  Curves
                  Unit Hydrographs            Time Series
                  LID Controls                 Time Patterns
                                              Map Labels
6.2    Adding Objects

Visual objects are those  that can appear on the Study Area  Map  and include Rain  Gages,
Subcatchments, Nodes, Links, and Map Labels. With the exception of Map Labels, there are two
ways to add these objects into a project:
    •   selecting the object's icon from the Object Toolbar and then clicking on the map,

    •   selecting the object's category in the Data Browser and clicking the Browser's  * button.

The first method makes the object appear on the map and is therefore recommended. With the
second method, the object will not appear on the map until X,Y coordinates are entered manually
by editing the  object's properties. What follows are more specific instructions  for adding each
type of object to a project.

Adding a Rain Gage

To add a Rain Gage using the  Object Toolbar:

    l. Click •:-.• on the toolbar.
    2. Move the mouse to the desired location on the map and click.

To add a Rain Gage using the  Data Browser:
    l. Select Rain Gages from the list of categories.
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    2. Click the * button.
    3. Enter the rain gage's X and Y coordinates in the Property Editor if you want it to appear
       on the study area map.

Adding a Subcatchment
To add a Subcatchment using the Object Toolbar:
    l. Click Hi on the toolbar.
    2. Use the mouse to draw a polygon outline of the Subcatchment on the map:
    3. left-click at each vertex
    4 . right-click or press  to close the polygon
    5. press the  key if you wish to cancel the action.
To add a Subcatchment using the Data Browser:
    l. Select Subcatchments from the list of object categories.
    2 . Click the * button.
    3. Enter the X and Y coordinates of the subcatchment's centroid in the Property Editor if
       you want it to appear on the study area map.

Adding a Node
To add a Node using the Object Toolbar:
    l. Click the button for the type  of node to add (if its not already depressed):
       O for a junction
       V  for an outfall
        v  for a flow divider
       t^J for a storage unit.
    2. Move the mouse to the desired location on the map and click.
To add a Node using the Data Browser:
    l. Select the type of node (Junction, Outfall, Flow Divider, or Storage Unit from the
       categories list of the Data Browser.
    2. Click the * button.
    3. Enter the node's X and Y coordinates in the Property Editor if you want it to appear on
       the study area map.
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Adding a Link
To add a Link using the Object Toolbar:
    l.  Click the button corresponding to the type of link to add (if its not already depressed):
       1—1  for a Conduit
       ^ for a Pump
       *2r  for an Orifice
       S  for a Weir
       &  for an Outlet.
    2 .  On the study area map, click the mouse on the link's inlet (upstream) node.
    3.  Move the mouse in the direction of the link's outlet (downstream) node, clicking at all
       intermediate points needed to define the link alignment.
    4.  Click the mouse a final time over the link's outlet (downstream) node.
Pressing the right mouse button or the  key while drawing a link will cancel the operation.
To add a Link using the Data Browser:
    l.  Select the type of link to add from the categories listed in the Data Browser.
    2.  Click the * button.
    3.  Enter the names of the inlet and outlet nodes of the link in the Property Editor.

Adding a Map Label
To add a text label to the Study Area Map:
    l.  Click the Text button  T on the Object Toolbar.
    2.  Click the mouse on the map where the top left corner of the label should appear.
    3.  Enter the text for the label.
    4.  Press  to accept the label or  to cancel.

Adding a Non-visual Object
To  add an  object belonging to a class that is not displayable on the Study Area Map  (which
includes  Climatology,  Aquifers,  Snow Packs,  LID  Controls, Unit  Hydrographs,  Transects,
Control Rules, Pollutants, Land Uses, Curves, Time Series, and Time Patterns):
    l.  Select the object's category from the list in the Data Browser.
    2.  Click the * button.
    3.  Edit the object's properties in the special editor dialog form that appears (see Appendix C
       for descriptions of these editors).
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6.3    Selecting and Moving Objects
To select an object on the map:
    l.  Make sure that the map is in Selection mode (the mouse cursor has the shape of an arrow
       pointing up to the  left). To switch to this mode, either click the Select Object button *
       on the Map Toolbar or choose Edit» Select Object from the Main Menu.
    2.  Click the mouse over the desired object on the map.
To select an object using the Data Browser:
    1.  Select the object's  category from the upper list in the Browser.
    2.  Select the object from the lower list in the Browser.
Rain gages, subcatchments, and nodes can be moved to another location on the Study Area Map.
To move an object to another location:
    l.  Select the object on the map.
    2.  With the left mouse button held down over the object, drag it to its new location.
    3.  Release the mouse button.
The following alternative method can also be used:
    l.  Select the object to be moved from the Data Browser (it must either be a rain gage,
       subcatchment, node, or map label).
    2.  With the left mouse button held down, drag the item from the Items list box of the Data
       Browser to its new location on the map.
    3.  Release the mouse button.
Note that the second  method can be used to place objects on the map that were imported from a
project file that had no coordinate information included in it.
6.4    Editing Objects
To edit an object appearing on the Study Area Map:
    l.  Select the object on the map.
    2 .  If the Property Editor is not visible either:
       •   double click on the object
       •   or right-click on the object and select Properties from the pop-up menu that appears
                      jd£,
       •   or click on  * in the Data Browser.
    3.  Edit the object's properties in the Property Editor.
Appendix B lists the properties associated with each of SWMM's visual objects.
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To edit an object listed in the Data Browser:
    l.  Select the object in the Data Browser.
    2.  Either:
       •   click on *€ in the Data Browser,
       •   or double-click the item in the Objects list,
       •   or press the  key.

Depending on the class of object selected, a special property editor will  appear  in which the
object's properties can be modified. Appendix C describes all of the special property editors used
with SWMM's non-visual objects.

W,-•?-.
       The unit system in which object properties are expressed depends on the choice of units
       for flow rate.  Using a flow rate expressed in cubic feet, gallons or acre-feet implies that
       US units  will be used for all quantities. Using  a flow rate expressed in liters or cubic
       meters means that SI metric units will  be used. Flow  units are selected either from the
       project's  default Node/Link properties (see Section  5.4)  or directly from the main
       window's  Status Bar (see Section 4.4). The units used for all properties are listed in
       Appendix A.I.
6.5     Converting an Object

It is possible to convert a node or link from one type to another without having to first delete the
object and add a new one in its place. An example would be converting a Junction node into an
Outfall node, or converting an Orifice link into a Weir link. To convert a node or link to another
type:
    l.  Right-click the object on the map.
    2.  Select Convert To from the popup menu that appears.
    3.  Select the new type of node or link to convert to from the sub-menu that appears.
    4.  Edit the object to provide any data that was not included with the previous type of object.

Only  data that is common to both types of objects will be preserved after an object is converted to
a different type. For  nodes this includes its name, position, description,  tag, external inflows,
treatment functions,  and invert elevation.  For  links it includes just its name,  end  nodes,
description, and tag.
6.6     Copying and Pasting Objects

The  properties of an object displayed on the Study Area Map can be copied and pasted into
another object from the same category.

To copy the properties of an object to SWMM's internal clipboard:
    l.   Right-click the object on the map.
    2.   Select Copy from the pop-up menu that appears.
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To paste copied properties into an object:
    l.   Right-click the object on the map.
    2.   Select Paste from the pop-up menu that appears.

Only data that can be shared  between objects  of the same type can be  copied  and pasted.
Properties not copied include the object's name, coordinates, end nodes (for links), tag property
and any descriptive comment associated with the object. For Map Labels, only font properties are
copied and pasted.
6.7    Shaping and Reversing Links

Links can be drawn as polylines containing any number of straight-line segments that define the
alignment or curvature of the link. Once a link has been drawn on the map, interior points that
define these line segments can be added, deleted, and moved. To edit the interior points of a link:
    l. Select the link to edit on the map and put the map in Vertex Selection mode either by
       clicking P^  on the Map Toolbar, selecting Edit » Select Vertex from the Main Menu,
       or right clicking on the link and selecting Vertices from the popup menu.
    2. The mouse pointer will change shape to an arrow tip, and  any existing vertex points on
       the link will be displayed as small open squares. The currently  selected vertex will be
       displayed as a filled square. To select a particular vertex, click the mouse over it.
    3. To add a new vertex to the link, right-click the mouse and select Add Vertex from the
       popup menu (or simply press the  key on the keyboard).
    4. To delete the currently selected vertex, right-click the mouse and select Delete Vertex
       from the popup menu (or simply press the  key on the keyboard).
    5. To move  a  vertex to  another  location, drag it to its new  position with  the left  mouse
       button held down.
While in Vertex Selection mode you can begin editing the vertices for  another  link by  simply
clicking on  the link. To  leave Vertex Selection mode, right-click on the map and select Quit
Editing from the popup menu, or simply select one of the other buttons on the Map Toolbar.

A link can also have its direction reversed (i.e., its end nodes switched) by right clicking on it and
selecting Reverse from the pop-up menu that appears. Normally, links should be oriented  so that
the upstream end is at a higher elevation than the downstream end.
6.8    Shaping a Subcatchment

Subcatchments are drawn on the Study Area Map as closed polygons. To edit or add vertices to
the polygon, follow the same procedures used for links. If the subcatchment is originally drawn or
is edited to have two or less vertices, then only its centroid symbol will be displayed on the Study
Area Map.
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6.9     Deleting an Object

To delete an object:
    l .   Select the object on the map or from the Data Browser.

    2 .   Either click  the  ~  button on the Data Browser  or  press the  key  on the
        keyboard, or right-click the object on the map and select Delete from the pop-up menu
        that appears.
       You can require that all deletions be confirmed before they take effect. See the General
       Preferences page of the Program Preferences dialog box described in Section 4.9.
6.10    Editing or Deleting a Group of Objects

A group of objects located within an irregular region of the Study Area Map can have a common
property edited or be deleted all together. To select such a group of objects:

    l.   Choose Edit» Select Region from the Main Menu or click  £5 on the Map Toolbar.
    2.   Draw  a polygon 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  key; cancel the
        selection by pressing the  key.

To select all objects in the project, whether in view or not, select Edit » Select All from the
Main Menu.

Once a group of objects has been selected, you can edit a common property shared among them:
    1.   Select Edit » Group Edit from the Main Menu.
    2.   Use the Group Editor dialog that appears to select a property and specify its new value.

The  Group Editor dialog, shown below, is used to modify a property for a  selected  group of
objects. To use the dialog:
    l.   Select  a  class  of object  (Subcatchments, Infiltration, Junctions,  Storage  Units,  or
        Conduits) to edit.
    2.   Check the  "with Tag equal to" box if you want to add a filter that will limit the objects
        selected for editing to those with a specific Tag value.  (For  Infiltration, the Tag will be
        that of the subcatchment to which the infiltration parameters belong.)
    3.   Enter a Tag value to filter on if you have selected that option.
    4.   Select the property to edit.
    5.   Select whether to replace, multiply, or add to the existing value of the property. Note that
        for some non-numerical properties the only available choice is to replace the value.
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        In the lower-right edit box, enter the value that should replace, multiply, or be added to
        the existing value for  all  selected objects. Some properties will have an ellipsis button
        displayed in the edit box which should be clicked to bring up a specialized editor for the
        property.

        Click OK to execute the group edit.
                      Group Editor
                        For objects of type
                        CH with Tag equal to
                        edit the property
Subcatchment
v
% Imperv
V
by replacing it with
V
                                                  75
                               OK
Cancel
Help
To  delete the objects located within a selected area of the map, select Edit » Group Delete
from the Main Menu. Then select the categories of objects you wish to delete  from the dialog box
that appears. As an option, you can specify that only objects within the selected area that have a
specific Tag property should be deleted. Keep in mind that deleting a node will also delete any
links connected to the node.
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CHAPTER 7 - WORKING WITH THE MAP
EPA SWMM can display a map of the study area being modeled. This section describes how you
can manipulate this map to enhance your visualization of the system.
7.1    Selecting a Map Theme

A map theme displays object properties in color-coded fashion on the Study Area Map. The
dropdown list boxes on  the  Map  Browser are used for selecting a theme  to  display for
Subcatchments, Nodes and Links.
                 SWMM 5  Example1! .inp
              File  Edit  View  Project  Report  Tools  Window  Help
               Data   Map
                Themes
                Subcatchments
                 Runoff
                Nodes
                 Depth
                Links
                 Flow
                              -
                                     O Study Area Map
Methods for changing the  color-coding  associated with a theme are discussed in Section 7.9
below.
7.2    Setting the Map's Dimensions

The physical dimensions of the map can be defined so that map coordinates can be properly
scaled to the computer's video display. To set the map's dimensions:
    1.  Select View » Dimensions from the Main Menu.
    2 .  Enter coordinates for the lower-left and upper-right corners of the map into the Map
       Dimensions dialog (see below) that appears or click the Auto-Size button to
       automatically set the dimensions based on the coordinates of the objects currently
       included in the map.
    3.  Select the distance units to use for these coordinates.
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        If the Auto-Length option is in effect, check the "Re-compute all lengths and areas" box
        if you would like SWMM to re-calculate all conduit lengths and subcatchment areas
        under the new set of map dimensions.
        Click the OK button to resize the map.
              Map Dimensions
                Lower Left

                 X-coordinate:

                 Y-coordinate:


                Map Units

                OFeet
                Upper Right

                 X-coordinate:
                 Y-coordinate:
                10000.000
O Meters
O Degrees
0None
                  d] Auto-Length is ON. Re-compute all lengths and areas?
                 Auto-Size
        If you are going to use a backdrop image with the automatic distance and area calculation
        feature,  then it is recommended that you set the  map  dimensions immediately after
        creating a new project. Map distance units can be different from conduit length units. The
        latter (feet or meters) depend on whether flow rates  are expressed in US or metric units.
        SWMM will automatically convert units if necessary.
7.3     Utilizing a Backdrop Image

SWMM can display a backdrop image behind
the Study Area Map. The backdrop image
might be a street map, utility map, topographic
map,  site  development  plan,  or any other
relevant picture or drawing. For example, using
a  street map  would  simplify the process of
adding  sewer lines to the  project  since  one
could essentially digitize the drainage system's
nodes and links directly on top of it.
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The backdrop image must be a Windows metafile, bitmap, or JPEG image created outside of
SWMM. Once imported, its  features cannot be edited, although its scale and viewing  area will
change as the map window  is zoomed and panned. For this reason metafiles work better than
bitmaps or JPEGs since they will not loose  resolution when re-scaled. Most CAD  and GIS
programs have the ability to save their drawings and maps as metafiles.

Selecting View » Backdrop from the Main Menu will display a sub-menu with the following
commands:
    •   Load (loads a backdrop image file into the project)
    •   Unload (unloads the  backdrop image from the project)
    •   Align (aligns the drainage system schematic with the backdrop)
    •   Resize (resizes the map dimensions of the backdrop)
    •   Watermark (toggles the backdrop image appearance between normal and lightened)

To  load  a backdrop image,  select View » Backdrop  »  Load  from the Main  Menu. A
Backdrop Image Selector dialog form will be displayed. The entries on this form are as follows:
                       Backdrop Image Selector
                         Backdrop I mage File
                         sample, wmf
                         World Coordinates File (optional)
                         sample, bpw
                         O Scale Map to Backdrop Image
                              OK
Cancel
Help
Backdrop Image File

Enter the name of the file that contains the image. You can click the I—' button to bring up a
standard Windows file selection dialog from which you can search for the image file.

World Coordinates File
                                                               ET]
If a "world" file exists for the image, enter its name here, or click the '—' button to search for it.
A world  file contains geo-referencing information for the image and can be created from  the
software  that produced the image file or by using  a text editor. It contains six lines with  the
following information:

Line 1: real world width of a pixel in the horizontal direction.
Line 2: X rotation parameter (not used).
Line 3: Y rotation parameter (not used).

Line 4: negative of the real world height of a pixel in the vertical direction.
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Line 5: real world X coordinate of the upper left corner of the image.
Line 6: real world Y coordinate of the upper left corner of the image.
If no world file is specified, then the backdrop will be scaled to fit into the center of the map
display window.

Scale Map to Backdrop Image

This option is only available when a world  file  has been specified. Selecting it forces the
dimensions of the Study Area Map to coincide with those of the backdrop image. In addition, all
existing objects on the map will have their coordinates adjusted so that they appear within the
new map dimensions yet maintain their relative positions to one another. Selecting this option
may then require that the  backdrop be re-aligned so that its position relative to the drainage area
objects is correct. How to do this is described below.

The backdrop image can  be re-positioned relative to the drainage system by selecting View »
Backdrop » Align. This allows the backdrop image to be moved across the drainage system (by
moving the mouse with the left button held down) until one decides that it lines up properly.

The backdrop image can also be resized by selecting View » Backdrop » Resize. In this case
the  following Backdrop Dimensions dialog will appear.
The dialog lets you manually enter the X,Y coordinates of the backdrop's lower left and upper
right corners.  The Study Area  Map's dimensions  are  also  displayed for reference. While the
dialog is visible you can view map coordinates by moving the mouse over the map window and
noting the X,Y values displayed in SWMM's Status Panel (at the bottom of the main window).
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Selecting the Resize Backdrop Image Only button will resize only the backdrop, and not the
Study Area Map, according to the coordinates specified. Selecting the Scale Backdrop Image to
Map button will position the backdrop image in the center of the Study Area Map and have it
resized to fill the display window  without changing its aspect ratio. The map's lower left and
upper right coordinates will be placed in the data entry fields for the backdrop coordinates, and
these  fields  will become  disabled.  Selecting  Scale  Map to Backdrop Image makes  the
dimensions of the map coincide with the dimensions being set for the backdrop image. Note that
this option will change the coordinates of all objects currently on the map so that their positions
relative  to one another remain unchanged.  Selecting this  option  may then require that  the
backdrop be re-aligned so that its position relative to the drainage area objects is correct.

 'T'1
 W    Exercise caution when selecting the Scale Map to Backdrop Image option in either the
       Backdrop Image Selector dialog or the Backdrop Dimensions dialog as it will modify the
       coordinates  of all existing objects currently on the Study Area Map. You might want to
       save  your project before carrying out this step in case the results  are not what you
       expected.

The name of the backdrop image file and its map dimensions are saved along with the rest of a
project's data whenever the  project is saved to file.

For best results  in using a backdrop image:

    •   Use a metafile, not a bitmap.

    •   If the image is loaded before any objects are added to the project then scale the map to it.
7.4     Measuring Distances

To measure a distance or area on the Study Area Map:

              if
    l.   Click ra on the Map Toolbar.

    2 .   Left-click on the map where you wish to begin measuring from.

    3.   Move the mouse over the distance being measured, left-clicking at each intermediate
        location where the measured path changes direction.

    4 .   Right-click the mouse or press  to complete the measurement.

    5.   The distance measured in project units (feet or meters) will be displayed in a dialog box.
        If the last point on the measured path coincides with the first point then the area of the
        enclosed polygon will also be displayed.
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7.5    Zooming the Map

To Zoom In on the Study Area Map:

    1.  Select View » Zoom In from the Main Menu or click ^% on the Map Toolbar.

    2.  To zoom in 100% (i.e., 2X), 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 Study Area Map:

    1.  Select View » Zoom Out from the Main Menu or click ^H,, on the Map Toolbar.

    2.  The map will be returned to the view in effect at the previous zoom level.
7.6    Panning the Map

To pan across the Study Area Map window:

    1.  Select View » Pan from the Main Menu or click *T* on the Map Toolbar.

    2 .  With the left button held down over any point on the map, drag the mouse in the direction
       you wish to pan in.

    3.  Release the mouse button to complete the pan.

To pan using the Overview Map (which is described in Section 7.10 below):
    l.  If not already visible, bring up the Overview Map by selecting View » Overview Map
       from the Main Menu.
    2.  If the Study Area Map has been zoomed in, an outline of the current viewing area will
       appear on the Overview Map. Position the mouse within this outline on the Overview
       Map.
    3.  With the left button held down, drag the outline to a new position.
    4.  Release the mouse button and the Study  Area  Map will be  panned to an  area
       corresponding to the outline on the Overview Map.
7.7    Viewing at Full Extent

To view the Study Area Map at full extent, either:
    •   select View » Full Extent from the Main Menu, or

    •   press H on the Map Toolbar.
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7.8    Finding an Object
To find an object on the Study Area Map whose name is
known:

    l. Select View »  Find Object  from the Main
       Menu or click *4  On the Standard Toolbar.
    2 . In the Map Finder dialog that appears, select the
       type of object to find and enter its name.
    3. Click the Go button.
Map Finder
If the object exists, it will be highlighted on the map and in the Data Browser. If the map is
currently zoomed in and the object falls outside the current map boundaries, the map will be
panned so that the object comes into view.


       User-assigned object  names in SWMM  are  not case sensitive.  E.g., NODE123  is
       equivalent to Nodel23.

After an object is found, the Map Finder dialog will also list:
    •  the outlet connections for a subcatchment
    •  the connecting links for a node
    •  the connecting nodes for a link.


7.9    Submitting a Map Query

A Map Query identifies objects on the study area map that meet a specific criterion (e.g., nodes
which flood, links with velocity below 2 ft/sec, etc.). It can also identify which subcatchments
have LID controls and which nodes have external inflows. 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 OJ on the Map Toolbar.
    3.  Fill in the following information in the Query dialog that appears:
       •   Select whether to search for Subcatchments, Nodes, Links, LID Subcatchments or
           Inflow Nodes.
       •   Select a parameter to query or the type of LID or inflow to locate.
       •   Select the appropriate operator: Above, Below, or Equals.
       •   Enter a value to compare against.
    4.  Click the Go button. The number of objects that meet the criterion will  be displayed in
       the Query dialog and each such object will be highlighted on the Study Area 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.
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             <> Study Area Map

                                                      01/01/199804:00:00

Find
With

Nodes
V

Flooding

Above

0

V
LtJ
1 items found
After the Query box is closed the map will revert back to its original display.
7.10   Using the Map Legends
                  Map  Legends associate a  color with a  range  of values  for the
                  current  theme  being  viewed.   Separate  legends  exist  for
                  Subcatchments, Nodes,  and Links.  A Date/Time Legend is also
                  available for displaying the date and clock time of the simulation
                  period being viewed on the map.
To display or hide a map legend:

    l.  Select View » Legends from the Main Menu or right-click on the map and select
       Legends from the pop-up menu that appears
    2.  Click on the type of legend whose display should be toggled on or off.

A visible legend can also be hidden by double clicking on it.

To move a legend to another location press the left mouse button over the legend, drag the legend
to its new location with the button held down, and then release the button.

To edit a legend, either select View » Legends » Modify from the Main Menu or right-click
on the legend if it is visible.  Then use the Legend Editor dialog that appears to  modify the
legend's colors and intervals.
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                       Click on color you wish to change
The Legend Editor is used to  set numerical ranges to which different colors are assigned for
viewing a particular parameter on the network map. It works as follows:

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

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

    •   Click the Auto-Scale button to automatically assign ranges based on the  minimum and
       maximum values attained by the parameter in question at the current time period.

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

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

    •   Check Framed if you want a frame drawn around the legend.
7.11   Using the Overview Map

The Overview Map, as pictured below, allows one to see where in terms of the overall system the
main Study Area Map is currently focused. This zoom area is depicted by the rectangular outline
displayed on the Overview Map. As you drag this rectangle to another position the view within
the main map will be redrawn accordingly. The  Overview Map can be toggled on  and off by
selecting View » Overview Map from the Main  Menu. The Overview Map window can also be
dragged to any position as well as be re-sized.
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7.12    Setting Map Display Options

The Map Options dialog (shown below) is used to change the appearance of the Study Area Map.
There are several ways to invoke it:
                    Map Options
                      Subcatchments
                      Nodes

                      Links

                      Labels


                      Annotation

                      Symbols


                      Flow Arrows

                      Background
OK
               Fill Style
               0 Clear

               O Solid

               O Diagonal

               O Cross Hatch
              Symbol
              Size

              Outline
              Thickness
             0 Display link to outlet
                                           Cancel
Help
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    •   select Tools » Map Display Options from the Main Menu or,

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

The dialog contains a separate page, selected from the panel on the left side of the form, for each
of the following display option categories:
    •   Subcatchments (controls  fill style, symbol  size, and outline thickness  of subcatchment
       areas)
    •   Nodes (controls size of nodes and making size be proportional to value)
    •   Links (controls thickness  of links and making thickness be proportional to value)
    •   Labels (turns display of map labels on/off)
    •   Annotation (displays or hides node/link ID labels and parameter values)

    •   Symbols (turns display of storage unit, pump, and regulator symbols on/off)
    •   Flow Arrows (selects visibility and style of flow direction arrows)
    •   Background (changes color of map's background).
Subcatchment Options

The Subcatchments page of the Map Options dialog controls how subcatchment areas are
displayed on the study area map.
    Option
    Fill Style
    Symbol Size

    Outline Thickness
    Display Link to
    Outlet
Description
Selects style used to fill interior of subcatchment area
Sets the size of the symbol (in pixels) placed at the centroid of a
subcatchment area
Sets the thickness of the line used to draw a subcatchment's
boundary; set to zero if no boundary should be displayed
If checked then a dashed line is drawn between the subcatchment
centroid and the subcatchment's outlet node (or outlet
subcatchment)
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Node Options
The Nodes page of the Map Options dialog controls how nodes are displayed on the study area
map.
    Option
    Node Size
    Proportional to
    Value
    Display Border
Description
Selects node diameter in pixels
Select if node size should increase as the viewed parameter
increases in value
Select if a border should be drawn around each node
(recommended for light-colored backgrounds)
Link Options
The Links page of the Map Options dialog controls how links are displayed on the map.
    Option
    Link Size
    Proportional to
    Value
    Display Border
 Description
 Sets thickness of links displayed on map (in pixels)
 Select if link thickness should increase as the viewed parameter
 increases in value
 Check if a black border should be drawn around each link
Label Options
The Labels page of the Map Options dialog controls how user-created map labels are displayed
on the study area map.
    Option
    Use Transparent
    Text
    At Zoom Of
  Description
  Check to display label with a transparent background (otherwise
  an opaque background is used)
  Selects minimum zoom at which labels should be displayed;
  labels will be hidden at zooms smaller than this
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Annotation Options
The Annotation page of the Map Options dialog form determines what kind of annotation is
provided alongside of the objects on the study area map.
    Option
    Rain Gage IDs
    Subcatch IDs
    Node IDs
    Link IDs
    Subcatch Values
    Node Values
    Link Values
    Use Transparent Text

    Font Size
    At Zoom Of
Description
Check to display rain gage ID names
Check to display subcatchment ID names
Check to display node ID names
Check to display link ID names
Check to display value of current subcatchment variable
Check to display value of current node variable
Check to display value of current link variable
Check to display text with a transparent background
(otherwise an opaque background is used)
Adjusts the size of the font used to display annotation
Selects minimum zoom at which annotation should be
displayed; all annotation will be hidden at zooms smaller
than this
Symbol Options

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

    Option                  Description
    Display Node Symbols   If checked then special node symbols will be used
    Display Link Symbols    If checked then special link symbols will be used
    At Zoom Of            Selects minimum zoom at which symbols should be
                           displayed; symbols will be hidden at zooms smaller than this
Flow Arrow Options

The Flow Arrows  page of the  Map  Options  dialog controls how flow-direction arrows are
displayed on the 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
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       Flow direction arrows will only be displayed after a successful simulation has been made
       and a computed parameter has been selected for viewing. Otherwise the direction arrow
       will point from the user-designated start node to end node.
Background Options

The Background page of the Map Options dialog offers a selection of colors used to paint the
map's background with.
7.13   Exporting the Map

The full extent view of the study area map can be saved to file using either:

    •   Autodesk's DXF (Drawing Exchange Format) format,
    •   the Windows enhanced metafile (EMF) format,

    •   EPA SWMM's own ASCII text (.map) 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 lose resolution when they are displayed at
different scales.

To export the map to a DXF, metafile, or text file:

    l.  Select File » Export» Map.
    2.  In the Map Export dialog that appears select the format that you want the map saved in.
                   Map Export
                      Export Map To:

                       O Text File (.map)

                       O Enhanced Metafile (.emf)

                       0 Drawing Exchange File (.dxf)

                           Draw Junctions As:

                           0 Open circles

                           O Filled circles

                           O Filled squares
                                          106

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If you select DXF format, you have a choice of how nodes will be represented in the DXF file.
They can be drawn as filled circles, as open circles, or as filled squares. Not all DXF readers can
recognize the format used in the DXF file to draw a filled circle. Also note that map annotation,
such as node and link ID labels will not be exported, but map label objects will be.

After choosing a format,  click OK  and enter a name for the file in the Save As dialog that
appears.
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               108

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CHAPTER 8 - RUNNING A SIMULATION
After a study area has been suitably described, its runoff response, flow routing and water quality
behavior can be simulated. This section describes  how to specify options  to be used in the
analysis, how to run the simulation and how to troubleshoot common problems that might occur.
8.1    Setting Simulation Options

SWMM has a number of options that control how the simulation of a stormwater drainage system
is carried out. To set these options:
    l.  Select the Options category from the Data Browser.
    2.  Select one of the following categories of options to edit:
           a.  General Options
           b.  Date Options
           c.  Time Step Options
           d.  Dynamic Wave Routing Options
           e.  Interface File Options
                    >^
       and click the "S button to invoke the Simulation Options dialog.


The Simulations Options  dialog contains  a separate tabbed page  for each  of these option
categories which are described in more detail below.


General Options

The General page of the Simulation Options dialog sets values for the following options:

Process Models
This section allows you to select which of SWMM's process models will be applied to the current
project. For example, a model that  contained Aquifer and Groundwater elements could be run
first with the groundwater computations turned on and then again with them turned off to see
what effect this process had on the site's hydrology. Note that if there are no elements in the
project needed to model a given process then that process option is disabled (e.g., if there were no
Aquifers defined for the project then the Groundwater check box will appear disabled in an
unchecked state).

Infiltration Model
This option controls how infiltration of rainfall into the upper soil  zone  of subcatchments is
modeled. The choices are:
    •  Horton
    •  Green-Ampt
    •  Curve Number
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Each of these models is briefly described in section 3.4.2. Changing this option will require re-
entering values for the infiltration parameters in each subcatchment.
             Simulation Options



General Dates | Time Steps | Dynamic Wave | Files |

0 Rainfall/Runoff
D Snow Melt
Ground water
0 Flow Routing
0 Water Quality
Infiltration Model
0 Morton
O Green Arnpt
O Curve Number

| 	 OK


O Allow Ponding
HH Report Control Actions
O Report Input Summary
O Skip Steady Periods
Minimum Conduit Slope
i*)

Routing Model
O Steady Flow
0 Kinematic Wave
O Dynamic Wave

	 -3
Cancel Help


Routing Method
This option determines which method is used to route flows through the conveyance system. The
choices are:
    •   Steady Flow
    •   Kinematic Wave
    •   Dynamic Wave
Review section 3.4.5 for a brief description of each of these alternatives.

Allow Ponding
Checking this option will allow excess water to collect atop nodes and be re-introduced into the
system as conditions permit. In order for ponding to actually occur at a particular node, a non-
zero value for its Ponded Area attribute must be used.
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Report Control Actions
Check this option if you want the simulation's Status Report to list all discrete control actions
taken by the Control Rules associated with a project (continuous modulated control actions are
not listed). This option should only be used for short-term simulation.

Report Input Summary
Check this option if you want the simulation's  Status Report to  list a summary of the project's
input data.

Skip Steady Periods
Checking this  option will make the simulation use the most recently computed conveyance
system flows during a steady state period instead of computing a new flow routing solution. A
time step is considered to be in steady state if the change in external inflows at each node is
below 0.5 cfs and the relative difference between total system inflow and outflow is below 5%.

Minimum Conduit Slope
The minimum value allowed for a conduit's slope (%). If blank or zero (the  default)  then no
minimum is imposed (although SWMM uses a lower limit on elevation drop  of 0.001 ft (0.00035
m) when computing a conduit slope).


Date Options

The Dates page of the Simulation Options dialog determines the  starting and ending dates/times
of a simulation.

Start Analysis On
Enter the date (month/day/year) and time of day  when the simulation begins.

Start Reporting On
Enter the date and time of day when reporting of simulation results is to begin. This must be on or
after the simulation starting date and time.

End Analysis On
Enter the date and time when the simulation is to end.

Start Sweeping On
Enter the day  of the year (month/day) when street sweeping operations begin.  The default is
January 1.

End Sweeping On
Enter the day  of the year (month/day) when  street sweeping operations  end. The  default is
December 31.

Antecedent Dry Days
Enter the number of days with no rainfall prior to the start of the simulation. This value is used to
compute  an initial buildup of pollutant load on the surface of subcatchments.

 ''T'1
 W    If rainfall or climate data are read from external files, then the simulation dates should be
       set to coincide with the dates recorded in these files.
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Time Step Options

The Time Steps page of the  Simulation Options dialog establishes the length of the time steps
used for runoff computation,  routing computation and results reporting. Time steps are specified
in days and hours:minutes:seconds except for flow routing which is entered as decimal seconds.

Reporting Time Step
Enter the time interval for reporting of computed results.

Runoff - Wet Weather Time Step
Enter the time step length used to compute runoff from subcatchments during periods of rainfall
or when ponded water still remains on the surface.

Runoff - Dry Weather Time Step
Enter the time step length used for runoff computations  (consisting essentially  of pollutant
buildup)  during periods when there  is no rainfall and no ponded water. This must be greater or
equal to the Wet Weather time step.

Routing Time Step
Enter the time step length  in decimal seconds  used  for routing flows and water quality
constituents through the conveyance system. Note that Dynamic Wave routing requires a much
smaller time step than the other methods of flow routing.


Dynamic Wave Options

The Dynamic Wave page of the Simulation Options dialog sets several parameters  that control
how the dynamic wave flow routing computations are made. These parameters have no effect for
the other flow routing methods.

Inertial Terms
Indicates how the inertial terms in the St. Venant momentum equation will be handled.
    •   KEEP maintains these terms at their full value under all conditions.
    •   DAMPEN reduces the terms as flow comes closer to being critical and ignores them
       when flow is supercritical.
    •   IGNORE drops the terms altogether from the momentum equation, producing what is
       essentially a Diffusion Wave solution.

Define Supercritical Flow By
Selects the basis used to determine when supercritical flow occurs in a conduit. The choices are:
    •   water surface slope only (i.e., water surface slope  > conduit slope)
    •   Froude number only (i.e., Froude number >  1.0)

    •   both water surface slope and Froude number.
The first two choices  were used in earlier versions of  SWMM  while the  third choice, which
checks for either condition, is now the recommended one.
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Force Main Equation
Selects  which equation will be used  to  compute  friction losses during pressurized  flow for
conduits that have been assigned a Circular Force Main cross-section. The choices are either the
Hazen-Williams equation or the Darcy-Weisbach equation.

Use Variable Time Step
Check the box if an internally computed variable time step should be used at each routing time
period and select an adjustment (or safety) factor to apply to this time step. The variable time step
is  computed  so  as to satisfy the  Courant condition within each  conduit.  A typical  adjustment
factor would be  75% to provide some margin of conservatism. The  computed variable time step
will not be less  than 0.5 seconds nor be greater than the fixed time step specified on the Time
Steps page of the dialog. If the latter was set lower than 0.5 seconds then the variable time step
option is ignored.

Time Step for Conduit Lengthening
This is a time step, in seconds, used to artificially lengthen conduits so that they meet the Courant
stability criterion under full-flow conditions (i.e., the travel time  of a wave will not be smaller
than the specified conduit lengthening time step). As this value is  decreased, fewer conduits will
require lengthening. A value of 0 means that no conduits  will be lengthened.  The ratio of the
artificial length to the original  length for each conduit is listed in the Flow Classification table
that appears in the simulation's  Status Report (see Section 9.1).

Minimum Surface Area
This is a minimum surface area used at nodes when computing changes in water depth. If 0 is
entered, then the default value of 12.566 ft2 (1.167 m2) is used. This is the area of a 4-ft diameter
manhole. The value entered should be in square feet for US units or square meters for SI units.


File Options

The Interface Files page of the  Simulation Options dialog is used to specify which  interface files
will be used  or  saved during the simulation. (Interface files  are described in  Chapter  11.) The
page contains a list box with three buttons underneath it. The list box lists the currently selected
files, while the buttons are used as follows:
Add    adds  a new interface file specification to the list.
Edit   edits the properties of the currently selected interface file.
Delete deletes the currently selected interface from the project (but not from your hard drive).

When the Add or Edit buttons  are clicked, an Interface File  Selector dialog appears where you
can specify the type of interface file, whether it should be used or saved, and its name.  The entries
on this dialog are as follows:
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               General  Dates  Time Steps  Dynamic Wave  Files
                Specify interface files to use or save:
                 >AVK HOTSTART
                                    \Hy Projects'
                                           Add
            Edit
Delete
                  Interface File Selector
                    File Type:
                   | HOTSTART       v |  0 Save File     O Use File

                   File Name:
                    | c:\My PmiectsSSWMMSStestlhsT
                              OK
Cancel
File Type
Select the type of interface file to be specified.

Use / Save Buttons
Select whether the named interface  file will  be used to supply  input to a simulation run  or
whether simulation results will be saved to it.

File Name
Enter the name of the interface file or click the Browse button  _ to select from a standard
Windows file selection dialog box.
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8.2    Setting Reporting Options
The Reporting  Options dialog shown below is used to select individual subcatchments, nodes,
and links that will have detailed time series results saved for viewing after a simulation has been
run. The default for new projects is that all objects will have detailed results saved for them. The
dialog is invoked by selecting the Reporting category  of Options from the Data Browser and
clicking the ^  button.
Reporting Options |x|
I
Select objects for detailed reporting:
Nodes Links
" '
Subcatchments
1
3
5
O All Subcatchments
Add

Remove

Clear

1 Close

Help

The dialog contains three tabbed pages - one each for subcatchments, nodes, and links.  It is a
stay-on-top form which means that you can select items directly from the Study Area Map or
Data Browser while the dialog remains visible.
To include an object in the set that is reported on:
    i.  Select the tab to which the object belongs (Subcatchments, Nodes or Links).
    2.  Unselect the "AH" check box if it is currently checked.
    3.  Select the specific object either from the Study Area Map or from the listing in the Data
       Browser.
    4.  Click the Add button on the dialog.
    5.  Repeat the above steps for any additional objects.
To remove an item from the set selected for reporting:
    i.  Select the desired item in the dialog's list box.
    2.  Click the Remove button to remove the item.
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To remove all items from the reporting set of a given object category, select the object category's
page and click the Clear button.

To include all objects of a given category in the reporting set, check the "All" box on the page for
that category (i.e., subcatchments, nodes, or links). This will override any individual items that
may be currently listed on the page.

To dismiss the dialog click the Close button.
8.3    Starting a Simulation

To start a simulation either select Project » Run Simulation from the Main Menu or click v
on the Standard Toolbar. A Run Status window will appear which displays the progress of the
simulation.
                         Run Status
                             !??•.   Computing ...
                           Percent Complete: 32%
                           [••••••••I
                           Simulated Time:
                            Days         0  Hrs:Min
07:53
To stop a run before its normal termination, click the Stop button on the Run Status window or
press the  key. Simulation results up until the time when the run  was stopped will  be
available for viewing. To minimize the SWMM program while a simulation is running, click the
Minimize button on the Run Status window.
If the analysis runs successfully the I  • icon will appear in the Run Status section of the Status
Bar at the bottom of SWMM's main window. Any error or warning messages will appear in a
Status Report window. If you modify the project after a successful run has been made, the faucet
icon changes to a broken faucet indicating that the current computed results no longer apply to the
modified project.
8.4    Troubleshooting Results

When a run ends prematurely, the Run Status dialog will indicate the run was unsuccessful and
direct the user to the Status Report for details. The Status Report will include an error statement,
code, and description of the problem (e.g., ERROR 138: Node TG040 has  initial depth greater
                                           116

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than maximum depth). Consult Appendix E for a description of SWMM's error messages. Even if
a run completes successfully, one should check to insure  that the results are reasonable. The
following are the most common reasons for a run to end prematurely or to contain questionable
results.

Unknown ID Error Message

This message typically appears when an object references another object that was never defined.
An example would  be a  subcatchment whose outlet was  designated as N29, but no  such
subcatchment or node with that name exists. Similar situations can exist for incorrect references
made  to  Curves, Time Series, Time Patterns, Aquifers, Snow Packs, Transects, Pollutants, and
Land Uses.

File Errors

File errors can occur when:
    •   a file cannot be located on the user's computer
    •   a file being used has the wrong format
    •   a file being written cannot be opened because the user does not have write privileges for
       the directory  (folder) where the file is to be stored.

SWMM needs to have write privileges for a directory (folder) where temporary files are stored
during a  run. The original default is the directory where Windows writes its temporary files. If
this directory does not exist or the user does not have write  privileges to it, then a new directory
must be assigned by using the Program Preferences dialog, which is discussed in Section 4.9.

Drainage System Layout Errors

A valid drainage system layout must obey the following conditions:
    •   An outfall node can have only one conduit link connected to it.
    •   A flow divider node must have exactly two outflow links.
    •   Under Kinematic Wave routing, a junction node can  only have one  outflow link and a
       regulator link cannot be the outflow link of a non-storage node.
    •   Under Dynamic Wave routing there must be at least one outfall node in the network.
An error message will be generated if any of these conditions are violated.

Excessive Continuity Errors

When  a  run completes successfully, the mass continuity errors for runoff, flow routing, and
pollutant routing will be displayed in the Run Status window.  These errors represent the percent
difference between initial storage + total inflow and  final storage + total outflow for the entire
drainage  system. If they exceed some reasonable level, such as 10 percent, then the validity of the
analysis results must be questioned. The most common reasons for an excessive continuity error
are computational time steps that are too long or conduits that are too short.
                                           117

-------
                                  Run was successful.
                            Continuity Error

                             Surface Runoff:
                             Flow Routing:
                             Quality Routing:
-0.25 %
•0.102
0.09%
                                            OK
In addition to the system continuity error, the Status Report produced by a run (see Section 9.1)
will list those nodes of the drainage network that have the largest flow continuity errors.  If the
error  for  a node is excessive, then  one should first consider if the  node in question is  of
importance to the purpose of the simulation. If it is, then further study is warranted to determine
how the error might be reduced.

Unstable Flow Routing Results

Due to the explicit nature of the numerical methods used for Dynamic Wave routing (and to a
lesser extent, Kinematic Wave routing), the flows in some links or water depths at some  nodes
may fluctuate or  oscillate significantly at certain periods  of time  as a result  of numerical
instabilities in the solution method. SWMM does not automatically identify when such conditions
exist,  so it is up  to the user to verify the numerical stability of the model and to determine if the
simulation results are valid for the modeling objectives.  Time series plots at key locations  in the
network can help  identify  such situations as can a scatter plot between  a  link's  flow  and the
corresponding water depth at its upstream node (see Section 9.4,  Viewing Results with a Graph).

Numerical instabilities can occur over short durations and may not be apparent when time  series
are plotted with  a long time interval. When detecting such instabilities, it is recommended that a
reporting time step of 1 minute or less be used, at least for an initial screening of results.

The run's Status Report lists the links having the five highest values of a Flow Instability  Index
(FII).  This index counts the number of times that the flow value  in a link is higher (or lower) than
the flow in both the previous and subsequent time periods. The  index is normalized with respect
to the expected number of such 'turns' that would occur  for a purely random series  of values and
can range from 0 to 150.

As an example of how the Flow Instability Index can be used, consider  the figure shown below.
The solid line plots the flow hydrograph for the link identified as having the highest FII value
(100)  in a dynamic wave flow routing run that used a fixed time step of 30 seconds. The dashed
line shows the hydrograph that results when a variable time step was used instead, which is now
completely stable.
                                           118

-------
          i
                                                        Fixed Time Step
                                                        (Fll = 100)
                                                        Variable Time Step
                                                            = 0)
             200 •
                                      4          6
                                          Time (hours)
Flow time series plots for the links having the highest FII's should be inspected to insure that
flow routing results are acceptably stable.
Numerical instabilities under Dynamic Wave flow routing can be reduced by:
    •  reducing the routing time step
    •  utilizing the variable time step option with a smaller time step factor
    •  selecting to ignore the inertial terms of the momentum equation
    •  selecting the option to lengthen short conduits.
                                           119

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(This page intentionally left blank.)
               120

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CHAPTER 9 - VIEWING RESULTS
This chapter describes the different ways in which the results  of a simulation  can be viewed.
These include  a status report, various map  views, graphs,  tables, and a statistical frequency
report.
9.1    Viewing a Status Report
A Status Report is available for viewing after each simulation. It contains:
    •   a summary of the main Simulation Options that are in effect
    •   a list of any error conditions encountered during the run
    •   a summary listing of the project's input data (if requested in the Simulation Options)
    •   a summary of the data read from each rainfall file used in the simulation
    •   a description of each control rule action taken during the simulation (if requested in the
       Simulation Options)
    •   the system-wide mass  continuity errors for:
       o   runoff quantity and quality
       o   groundwater flow
       o   conveyance system flow and water quality
    •   the names of the nodes with the highest individual flow continuity errrors
    •   the names of the conduits that most often determined the size of the time step used for
       flow routing (only when the Variable Time Step option is used)
    •   the names of the links  with the highest Flow Instability Index values
    •   information on the range of routing time steps taken and the percentage of these that were
       considered steady state.
In addition, the report contains several tables that display summary results for the quantities of
most  interest for each  subcatchment, LID control  unit, node,  and link. The tables  and  the
information they display are listed below.
                                          121

-------
Table
Columns
Subcatchment Runoff
Total precipitation (in or mm);
Total run-on from other subcatchments (in or mm);
Total evaporation (in or mm);
Total infiltration (in or mm);
Total runoff depth (in or mm);
Total runoff volume (million gallons or million liters);
Runoff coefficient (ratio of total runoff to total precipitation).
LID Performance
Total inflow volume
Total evaporation loss
Total infiltration loss
Total surface outflow
Total underdrain outflow
Initial storage volume
Final storage volume
Note: all quantities are expressed as depths (in or mm) over the LID
unit's surface area.	
Subcatchment Washoff
Total mass of each pollutant washed off the Subcatchment (Ibs or
Node Depths
Average water depth (ft or m);
Maximum water depth (ft or m);
Maximum hydraulic head (HGL) elevation (ft or m);
Time of maximum depth.	
Node Inflows
Maximum lateral inflow (flow units);
Maximum total inflow (flow units);
Time of maximum total inflow;
Total lateral inflow volume (million gallons or million liters);
Total inflow volume (million gallons or million liters).
Note: Total inflow consists of lateral inflow plus inflow from
connecting links.
Node Surcharging
Hours surcharged;
Maximum height of surcharge above node's crown (ft or m);
Minimum depth of surcharge below node's top rim (ft or m).
Note: surcharging occurs when water rises above the crown of the
highest conduit and only those conduits that surcharge are listed.
Node Flooding
Hours flooded;
Maximum flooding rate (flow units);
Time of maximum flooding;
Total flood volume (million gallons or million liters);
Maximum ponded volume (1000 ft3 or 1000 m3) or
Maximum ponded depth (ft or m)
Note: flooding refers to all water that overflows a node, whether it
ponds or not, and only those nodes that flood are listed.
                                          122

-------
Storage Volumes
Average volume of water in the facility (1000 ft3 or 1000 m3);
Average percent of full storage capacity utilized;
Maximum volume of water in the facility (1000 ft3 or 1000 m3);
Maximum percent of full storage capacity utilized;
Time of maximum water stored;
Maximum outflow rate from the facility (flow units).	
Outfall Loading
Percent of time that outfall discharges;
Average discharge flow (flow units);
Maximum discharge flow (flow units);
Total volume of flow discharged (million gallons or million liters);
Total mass discharged of each pollutant (Ibs or kg).	
Link Flows
Maximum flow (flow units);
Time of maximum flow;
Maximum velocity (ft/sec or m/sec)
Ratio of maximum flow to full normal flow;
Ratio of maximum flow depth to full depth.
Flow Classification
Ratio of adjusted conduit length to actual length;
Fraction of time spent in the following flow categories:
    •  dry on both ends
    •  dry on the upstream end
    •  dry on the downstream end
    •  subcritical flow
    •  supercritical flow
    •  critical flow at the upstream end
    •  critical flow at the downstream end
Average Froude number;
Average change in flow between each time step (flow units).
Conduit Surcharging
Hours that conduit is full at:
    •  both ends
    •  upstream end
    •  downstream end
Hours that conduit flows above full normal flow;
Hours that conduit is capacity limited
Note: only conduits with one or more non-zero entries are listed and
a conduit is considered capacity limited if its upstream end is full
and the HGL slope is greater than the conduit slope.	
Pumping Summary
Percent of time that the pump is on line;
Maximum flow pumped (flow units);
Average flow pumped (flow units);
Total energy consumed assuming 100% efficiency (kwatt-hours);
Percent of time that the pump operates off of its pump curve.
The  Status Report can be viewed  by selecting Report » Status from the Main Menu. Its
window includes a Bookmarks panel that makes it easy to navigate between the topics listed
above.
                                          123

-------
To copy selected text from the Status Report to a file or to the Windows Clipboard, first select the
text to copy with the mouse and then choose Edit » Copy To from the Main Menu (or press the
^ button on the Standard Toolbar). If the entire report is to be copied then it is not necessary to
first select text with the mouse.

To locate  an object that is listed in one of the Status Report's tables, first select the object's name
with the mouse and choose Edit » Find Object from the Main Menu (or press the $« button on
the Standard Toolbar and select Find Object from the dropdown menu). Then in the Map Finder
dialog that appears, select the type of object to look for (Subcatchment, Node or Link) and press
the Go button (the object's name will have already been entered in the form).  The  object will
appear highlighted in both the Data Browser and on the Study Area Map.
9.2    Variables That Can Be Viewed

Computed results at each reporting time step for the following variables are available for viewing
on the map and can be plotted, tabulated, and statistically analyzed:
        Subcatchment Variables
           rainfall rate (in/hr or mm/hr)
           snow depth (in or mm)
        •   losses (infiltration + evaporation in
           in/hr or mm/hr)
           runoff flow (flow units)
           groundwater flow into the drainage
           network (flow units)
        •   groundwater elevation (ft or m)
           washoff concentration of each
           pollutant (mass/liter)

        Node Variables
        •   water depth (ft or m above the node
           invert elevation)
        •   hydraulic head (ft or m, absolute
           elevation per vertical datum)
           water volume held in storage
           (including ponded water, ft3 or m3)
           lateral inflow (runoff + all other
           external inflows, in flow units)
           total inflow (lateral inflow +
           upstream inflows, in flow units)
           surface flooding (excess overflow
           when the node is at full depth, in
           flow units)
        •   concentration of each pollutant after
           any treatment applied at the node
           (mass/liter)
Link Variables
•   flow rate (flow units)
    average water depth (ft or m)
•   flow velocity (ft/sec or m/sec)
    Froude number (dimensionless)
•   capacity (ratio of depth to full depth)
    concentration of each pollutant
    (mass/liter)

System-Wide Variables
    air temperature (degrees F or C)
    evaporation rate (in/day or mm/day)
    total rainfall (in/hr or mm/hr)
•   total snow depth (in or mm)
    average losses (in/hr or mm/hr)
•   total runoff flow (flow units)
    total dry weather inflow (flow units)
•   total groundwater inflow (flow units)
    total I&I inflow (flow units)
•   total direct inflow (flow units)
    total external inflow (flow units)
•   total external flooding (flow units)
    total outflow from outfalls (flow
    units)
•   total nodal storage volume ( ft3 or m3)
                                           124

-------
9.3    Viewing Results on the Map

There are several ways to view the values of certain input parameters and simulation results
directly on the Study Area Map:
    •   For the current settings on the Map Browser, the subcatchments, nodes and links of the
       map will be colored according to their respective Map Legends. The map's color coding
       will be updated as a new time period is selected in the Map Browser.
    •   When the  Flyover Map  Labeling  program preference is  selected (see  Section  4.9),
       moving the mouse over  any map object will display  its ID name  and the value of its
       current theme parameter in a hint-style box.
    •   ID names and parameter values can be displayed next to all subcatchments, nodes and/or
       links  by selecting the appropriate options on the Annotation page  of the  Map Options
       dialog (see Section 7.11).

    •   Subcatchments,  nodes  or links  meeting  a specific criterion can be  identified  by
       submitting  a Map Query (see Section 7.8).

    •   You can animate the display of results on the network map either forward or backward in
       time by using the controls on the Animator panel of the Map Browser (see Section 4.7).
    •   The map can be printed, copied to the Windows clipboard, or saved as a DXF file or
       Windows metafile (see Section 7.12).
9.4    Viewing Results with a Graph

Analysis results can be viewed using several different types of graphs. Graphs can be printed,
copied to the Windows clipboard, or saved to a text file or to a Windows metafile. The following
types of graphs can be created from available simulation results:
                                            Link 1602 Flow
       Time Series Plot:
                             80.0
                             60.0
                             40.0
                             20.0
                              0.0
                                     123456
                                               Elapsed Time (hours)
                                           125

-------
                                   Water Elevation Profile: Node 81009 -16009
        Profile Plot:
                                                                        81009
                              100
                                          10,000           5,000
                                                  Distance (ft)
                                                               01/01/200201:30:00
                                    Link 1600 Flow v. Node 16109 Depth
        Scatter Plot:
CO
o buu
iZ 40 0
§
to
I* 9n n
ij
nn



jm key while drawing a zoom
rectangle with the mouse's left button held down. Drawing the rectangle from left to right zooms
in, drawing it from right to left zooms out. The plot  can  also be panned in any direction by
holding down the   key  and moving  the mouse  across the  plot with the left button held
down

An opened graph will normally be  redrawn when  a  new  simulation is run. To prevent  the
automatic updating of a graph once a new  set of results  is computed you can lock the current
graph by clicking the  © icon in the upper left corner of the graph.  To unlock the graph, click the
icon again.


Time Series Plots

A Time Series Plot graphs the value  of a particular variable at up to six locations against time.
When only a single location is plotted, and that location has calibration data registered for the
plotted variable, then the calibration  data will be plotted along with the simulated results  (see
Section 5.5 for instructions on how to  register calibration data with  a project).

To create a Time Series Plot:

    l. Select Report» Graph » Time Series from the Main Menu or click EC on the
       Standard Toolbar.
    2. A Time Series Plot dialog will appear. Use it to describe what objects and quantities
       should be plotted.
                                            126

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                       Time Series Plot
                  Start Date
                                             End Date
                       06/27/2002

                                          06/27/2002

                  Time Format
                                             Object Category
                       Elapsed Time

                                          Links
                      Variables
                                         Links
                         Depth
                         Velocity
                         Froude No.
                         Capacity

                                           Cancel
                                                      Help
The Time Series Plot dialog describes the objects and variable to be graphed in a time series plot.
Time series for certain system-wide variables, such as total rainfall, total runoff, total flooding,
etc., can also be plotted. Use the dialog as follows:
        Select a Start Date and End Date for the plot (the default is the entire simulation period).
        Choose whether to show time as Elapsed Time or as Date/Time values.
        Choose an Object Category (Subcatchment, Node, Link, or System) for plotting.
        If the object category is not System, identify the objects to plot by:
            a.  selecting the object either on the Study Area Map or in the Data Browser
l.
2.
3.
4.
           b.  clicking the — button on the dialog to add it to the plot,
           c.  repeating these steps for any additional objects of the same category.
    5.  Select a simulated variable to be plotted. The available choices depend on the category of
        object selected.
    6.  Click the OK button to create the plot.
A maximum of 6 objects can be selected for a single plot. Objects already selected can be deleted,
moved up in the order or moved down in the order by clicking the
respectively.
                                                            hi  l±J
, and
buttons,
                                            127

-------
Profile Plots

A Profile Plot displays the variation in simulated water depth with distance over a connected path
of drainage system links and nodes at a particular point in time. Once the plot has been created it
will be automatically updated as a new time period is selected using the Map Browser.

To create a Profile Plot:

    l.  Select Report » Graph » Profile from  the main menu  or press ^tj on the Standard
        Toolbar
    2.  A Profile Plot dialog will appear (see below). Use it to identify the path along which the
        profile plot is to be drawn.
                      Create Profile

                      Start Node
                                       Links in Profile
                      J1
                      End Node
                      Qutl
                            Find Path
                          Use Saved Profile
                                        C1
                                        C2
                                        C4
                         Save Current Profile
                              OK
                                   Cancel
The Profile Plot dialog is used to specify a path of connected conveyance system links along
which a water depth profile versus distance should be drawn. To define a path using the dialog:

    l.  Enter the ID of the upstream node of the first link in the path in the Start Node edit field

        (or click on the node on the Study Area Map and then on the — button next to the edit
        field).

    2.  Enter the ID of the downstream node of the last link in the path in the End Node edit field

        (or click the node on the map and then click the
                                                 button next to the edit field).
        Click the Find Path button to have the program automatically identify the path with the
        smallest number of links between the  start and end nodes.  These will  be listed in the
        Links in Profile box.

        You can insert a new link into the Links in Profile list by selecting the new link either on

                                                                          button underneath
the Study Area Map or in the Data Browser and then clicking the
the Links in Profile list box.
                                            128

-------
    5.  Entries in the Links in Profile list can be deleted or rearranged by using the L—J, L-J,
        and *—.J buttons underneath the list box.
    6.  Click the OK button to view the profile plot.
To save the current set of links listed in the dialog for future use:
    l.  Click the Save Current Profile button.
    2 .  Supply a name for the profile when prompted.
To use a previously saved profile:
    l.  Click the Use Saved Profile button.
    2.  Select the profile to use from the Profile Selection dialog that appears.
Profile plots can also be created before any simulation results are available, to help visualize and
verify the vertical layout of a drainage system. Plots created in this manner will contain a refresh
       *"**(
button     in the upper left corner that can be used to redraw the plot after edits are made to any
elevation data appearing in the plot.

Scatter Plots
A Scatter Plot displays the relationship between a pair of variables, such as flow rate in a pipe
versus water depth at a node. To create a Scatter Plot:
    l.  Select Report» Graph » Scatter from the main menu or press ti- on the Standard
        Toolbar
    2.  Specify what time interval and what pair of objects and their variables to plot using the
        Scatter Plot dialog that appears.
The  Scatter Plot dialog is used to select the objects  and variables to be graphed against one
another in a scatter plot. Use the dialog as follows:
    l.  Select a Start Date and End Date for the  plot (the default is the entire  simulation period).
    2.  Select the following choices for the X-variable  (the quantity plotted along the horizontal
        axis):
           a.  Object Category (Subcatchment, Node or Link)
           b.  Object ID (enter a value or click on the object either on the Study Area Map or in
               the Data Browser and then click the I—J button on the dialog)
           c.  Variable to plot (choices depend on the category of object selected).
    3.  Do the same for the Y-variable (the quantity plotted along the vertical axis).
    4.  Click the OK button to create the plot.
                                            129

-------
O Scatter Plot
Start Date
101/01/1998
X
Variable
Object Category
Nodes
Object
24 [+]
Variable
Depth

r~°K 	 i


End Date
1 01/02/1 998
Y-Variable
Object Category
Links
Object
16 [+]
Variable
Flow

lancel Help

9.5    Customizing a Graph's Appearance

To customize the appearance of a graph:

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

    2.  Select Report » Customize from the Main Menu, or click UsT on the Standard Toolbar,
       or right-click on the graph.

    3.  Use the Graph Options dialog that appears to customize the appearance of a Time Series
       or Scatter Plot, or use the Profile Plot Options dialog for a Profile Plot.


Graph Options Dialog

The Graph Options dialog is used to customize the appearance of a time series plot or a scatter
plot. To use the dialog:

    l.  Select from among the five tabbed pages that cover the following categories of options:
       General, Horizontal Axis, Vertical Axis, Legend, and 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.
                                           130

-------
                 Graph Options
                  General  Horizontal Axis  Vertical Axis  Legend  Series
                   Panel Color
                   Background Color
                   View in 3D
                   3D Effect Percent
                   Main Title
                                                      -
                                                      -
                    Link 1 Flow
                                  Font.
                 n Default
                                      OK
Graph Options - General

The following options can be set on the General page of the Graph Options dialog box:
       Panel Color
       Background Color
       View in 3D
       3D Effect Per cent
       Main Title
       Font
Color of the panel that contains the graph
Color of graph's plotting area
Check if graph should be drawn in 3D
Degree to which 3D effect is drawn
Text of graph's main title
Click to set the font used for the main title
                                           131

-------
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.

       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             Toggles the display of grid lines on and off.
       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.

       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 the symbol portion of the
                             legend.
       Framed              Places a frame around the legend.
        7isible                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:
    l.  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 (not all properties are
       available for some types of graphs). The choices are:
           •   Lines
           •   Markers
           •   Patterns
           •   Labels
                                          132

-------
Profile Plot Options Dialog

The Profile Plot Options dialog is used to customize the appearance of a Profile Plot. The dialog
contains three pages:
    Colors:
        •    selects the color to use for the plot window panel, the plot background, a conduit's
            interior, and the depth of filled water
        •    includes a "Display Conduits Only" check box that provides a closer look at the
            water levels within conduits by removing all other details from the plot.
    Axes:
        •    edits the main and axis titles, including their fonts
        •    selects to display horizontal and vertical axis grid lines.
    Node Labels:
        •    selects to display node ID labels either along the plot's top axis, directly on the plot
            above the node's crown height, or both.
        •    selects the length of arrow to draw between the node label and the node's crown on
            the plot (use 0 for no arrows).
        •    selects the font size of the node ID labels.
                    Colors  [Axes  || Node Labels
                      Plot Panel


                      Plot Background


                      Conduit Interior


                      Water Depth

                      Display Conduits Only
                                                  Button Face
           White
           Info Background
           Aqua
       D
                  D Default
OK
Check the Default box if you want these options to apply to all new profile plots when they are
first created.
                                             133

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9.6    Viewing Results with a Table

Time series results for selected variables and objects can also be viewed in a tabular format.
There are two types of formats available:
    •  Table by Object - tabulates the time series of several variables for a single object (e.g.,
       flow and water depth for a conduit).
O Table - Link *
Date
01/01/1998
01/01/1998
01/01/1998
01/01/1998
01/01/1998
01/01/1998
r
Time
01:00:00
02:00:00
03:00:00
04:00:00
05:00:00
06:00:00
^^m
Flow
(CFS)
	 : 	
2.58
4.87
5.41
5.23
1.74
OS
Depth
(ft)
0.00
0.40
0.55
0.58
0.57
0.33
j|
"





V
       Table by Variable - tabulates the time series of a single variable for several objects of the
       same type (e.g., runoff for a group of subcatchments).
0 Table Subcatch Runoff EJ@S
Date
01/01/1998
01/01/1998
01/01/1998
01/01/1998
01/01/1998
01/01/1998
Time
01:00:00
02:00:00
03:00:00
04:00:00
05:00:00
06:00:00
Subcatch Subcatch A
2 5
0.00
1.24 1.81
2.56 3.82
4.52 6.56
2.51 3.59
0.70 1.03 v
To create a tabular report:

    l.  Select Report» Table from the Main Menu or click HH! on the Standard Toolbar.

    2.  Choose the table format  (either By Object or By Variable) from the  sub-menu that
       appears.

    3.  Fill in the Table by Object or Table by Variable dialogs to specify what information the
       table should contain.

The Table by Object dialog is used when creating a time series table of several  variables for a
single object. Use the dialog as follows:
                                           134

-------
O Table by Object


Start Date
01/01/1998
Time Format
Date/Time
Variables

0 Flow^^^^^^
Velocity
Froude No.
Capacity
TSS
Lead

I 	 « 	 I


End Date
01/02/1998
Object Category
Links
Links
5

Cancel Help

    l.   Select a Start Date and End Date for the table (the default is the entire simulation period).
    2.   Choose whether to show time as Elapsed Time or as Date/Time values.
    3.   Choose an Object Category (Subcatchment, Node, Link, or System).
    4.   Identify a specific object in the category by clicking the object either on the Study Area
        Map or in the Data Browser and then clicking the '—I button on the dialog. Only a single
        object can be selected for this type of table.
    5.   Check off the  variables to  be tabulated for the selected object. The  available choices
        depend on the category of object selected.
    6.   Click the OK button to create the table.
The Table by Variable dialog is used when creating a time series table of a single variable for one
or more objects. Use the dialog as follows:
    l.   Select a Start Date and End Date for the table (the default is the entire simulation period).
    2.   Choose whether to show time as Elapsed Time or as Date/Time values.
    3.   Choose an Object Category (Subcatchment, Node or Link).
    4.   Select a simulated variable to be tabulated. The available choices depend on the category
        of object selected.
    5.   Identify one or more objects in the category by successively clicking the object either on
        the  Study Area Map or in the Data Browser and then clicking the — button on the
        dialog.
    6.   Click the OK button to create the table.
                                           135

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Table by Variable
Start Date
01/01/1998
Time Format
Date/Time
Variables
Rainfall A
Snow Depth
Losses
GW Flow
GW Elev.
TSS v

I 	 « 	 I


End Date
01/02/1998
Object Category
Subcatchments
Subcatchments
M

Cancel Help

A maximum of 6 objects can be selected for a single table. Objects already selected can be

                                                                                -, and
deleted, moved up in the order or moved down in the order by clicking the
buttons, respectively.
9.7    Viewing a Statistics Report

A Statistics Report can be generated from the time series of simulation results. For a given object
and variable this report will do the following:
    •  segregate the simulation period into a sequence of non-overlapping events, either by day,
       month, or by flow (or volume) above some minimum threshold value,
    •  compute a statistical value that characterizes each event, such as the mean, maximum, or
       total sum of the variable over the event's time period,
    •  compute summary statistics for the entire set of event values  (mean, standard deviation
       and skewness),
    •  perform  a frequency analysis on the set of event values.
The  frequency analysis of event values will determine the frequency at which a particular event
value has occurred and will also estimate a return period for each event value.  Statistical analyses
of this nature are most suitable for long-term continuous simulation runs.
To generate a Statistics Report:

    l .  Select Report » Statistics from the Main Menu or click
                                                                on the Standard Toolbar.
    2 . Fill in the Statistics Selection dialog that appears, specifying the object, variable, and
       event definition to be analyzed.
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The Statistics Selection dialog is used to define the type of statistical analysis to be made on a
computed simulation result. It contains the following data fields:
O Statistics Selection
0
0
V
E
S

bject Category Subcatchme

biect Name **1

ariable Analyzed Rainfall

^ent Time Period Event-Deper

atistic Mean


Rainfall °

Event Volume

Separation Time 6

! OK | Cancel

0 &

it

0

J

dent

V








Help

Object Category
Select the category of object to analyze (Subcatchment, Node, Link or System).

Object Name
Enter the ID name of the object to analyze. Instead of typing in an ID name, you can select the
object on the Study Area Map or in the Data Browser and then click the
into the Object Name field.
button to select it
Variable Analyzed
Enter the  name of the  variable to be analyzed. The  available choices  depend on  the  object
category selected (e.g., rainfall, losses, or runoff for subcatchments; depth, inflow, or flooding for
nodes; depth, flow, velocity, or capacity for links; water quality for all categories).

Event Time Period
Select  the length of the time period that  defines an event. The choices  are daily, monthly, or
event-dependent. In the latter case, the  event period  depends on  the number of consecutive
reporting periods where simulation results are above the threshold values defined below.
                                           137

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Statistic
Choose an event statistic to be analyzed. The available choices depend on the choice of variable
to be analyzed and include such quantities as mean value, peak value, event total, event duration,
and inter-event time (i.e., the time interval between the midpoints of successive events). For water
quality variables the choices include mean concentration, peak concentration, mean loading, peak
loading, and event total load.

Event Thresholds
These define minimum values that must be exceeded for an event to occur:
    •   The Analysis  Variable threshold  specifies the  minimum value of the variable being
       analyzed that must be exceeded for a time period to be included in an event.
    •   The Event Volume threshold specifies a minimum flow volume (or rainfall volume) that
       must be exceeded for a result to be counted as part of an event.
    •   Separation Time sets the minimum number of hours that must occur between the end of
       one event and  the start of the next  event. Events with fewer hours are combined together.
       This value applies only to event-dependent time periods (not to daily or monthly event
       periods).
If a particular type of threshold does not apply, then leave the field blank.

After the choices made on the Statistics Selection dialog form are processed, a Statistics Report is
produced as shown below.
          O Statistics - Subcatch S1 Rainfall
n x
           Summary  Events  Histogram  Frequency Plot^

             SUMMARY   STATISTICS

             Object  	  Subcatch SI
             Variable 	  Rainfall   (in/hr)
             Event Period 	  Variable
             Event Statistic 	  Hean   (in/hr)
             Event Threshold 	  Rainfall > 0.00   (in/hr)
             Event Threshold 	  Event Volume  >  0.00  (in)
             Event Threshold 	  Inter-Event Time > 6.0   (hr)
             Period of Record  	  01/01/1998 to 01/02/2000

             Number of Events  	  213
             Event Frequency*	  0.076
             Minimum Value  	  0. 010
             Maximum Value  	  0.500
             Mean Value 	  0. OS9
             Std.  Deviation	  O.OS9
             Skewness Coeff	  2.967

             *Fraction of all  reporting periods belonging to an event.

                                          138

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The report consists of four tabbed pages that contain:
    •   a table of event summary statistics
    •   a table of rank-ordered event periods, including their date, duration, and magnitude
    •   a histogram plot of the chosen event statistic
    •   an exceedance frequency plot of the event values.
Note that the exceedance frequencies included in the report are  computed with respect to the
number of events that occur, not the total number of reporting periods.
                                           139

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               140

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CHAPTER 10 - PRINTING AND COPYING
This chapter describes how to print, copy to the Windows clipboard, or copy to file the contents
of the currently active window in the SWMM workspace. This can include the study area map, a
graph, a table, or a report.
10.1   Selecting a Printer
To select a printer from among your installed Windows printers and set its properties:
    l.  Select File » Page Setup from the Main Menu.
    2.  Click the Printer button on the Page Setup dialog that appears (see Figure 10-1).
    3.  Select a printer from the choices available in the combo box in the Print Setup dialog that
       appears.
    4 .  Click the Properties button to select the appropriate printer properties (which vary with
       choice of printer).
    5.  Click OK on each dialog to accept your selections.
                Margins  Headers/Footers
                  Paper Size
                  Width: 8.5 "
                  Height: 11.0'
                  Orientation
                  0 Portrait

                  O Landscape
Margins (inches)
Left
Top
Right    LOO
Bottom   100
                                                                Cancel
                 Figure 10-1. The Margins page of the Page Setup dialog.
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10.2   Setting the Page Format
To format the printed page:
    1.  Select File » Page Setup from the main menu.
    2.  Use the Margins page of the Page Setup dialog form that appears (Figure 10-1) to:
    3.  Select a printer.
    4.  Select the paper orientation (Portrait or Landscape).
    5.  Set left, right, top, and bottom margins.
    6.  Use the Headers/Footers page of the dialog box (Figure 10-2) to:
    7.  Supply the text for a header that will appear on each page.
    8.  Indicate whether the header should be printed or not and how its text should be aligned.
    9.  Supply the text for a footer that will appear on each page.
    10. Indicate whether the footer should be printed or not and how its text should be aligned.
    11. Indicate whether pages should be numbered.
    12. Click OK to accept your choices.
               Page Setup
                 Margins  Headers/Footers
                   Header
                  Align:   Q Left     0 Center    Q Right       Enabled   0
                   Footer
                   SWMM5
                  Align:   0|_eft     O Center    O Right       Enabled   0
                   Page Numbers     Lower Rjght      v
                                                 j    OK          Cancel
             Figure 10-2. The Headers/Footers page of the Page Setup dialog.
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10.3   Print Preview

To preview a printout, select File » Print Preview from the Main Menu. A Preview form will
appear which shows how each page being printed will appear. While in preview mode, the left
mouse button will re-center and zoom in on the image and the right mouse button will re-center
and zoom out.
10.4   Printing the Current View

To print the contents of the current window being viewed in the SWMM workspace, either select
File » Print from the Main Menu or click & on the Standard Toolbar. The following views can
be printed:
    •   Study Area Map (at the current zoom level)
    •   Status Report.
    •   Graphs (Time Series, Profile, and Scatter plots)
    •   Tabular Reports
    •   Statistical Reports.
10.5   Copying to the Clipboard or to a File

SWMM can copy the text and graphics of the current window being viewed to the Windows
clipboard or to a file. Views that can be copied in this fashion include the Study Area Map,
graphs, tables, and reports. To copy the current view to the clipboard or to file:
    l.  If the current view is a table, select the cells of the table to copy by dragging the mouse
       over them or copy the entire table by selecting Edit» Select All from the Main Menu.

    2.  Select Edit  » Copy To from the Main Menu or click the ^ button on the Standard
       Toolbar.

    3.  Select choices from the Copy dialog  (see Figure  10-3) that appears  and click the  OK
       button.

    4.  If copying to file, enter the name of the file in the  Save As dialog that appears and click
       OK
Use the Copy dialog as follows to define how you want your data copied and to where:
    l.  Select a destination for the material being copied (Clipboard or File)
    2.  Select a format to copy in:
       •   Bitmap  (graphics only)
       •   Metafile (graphics only)
       •   Data (text, selected cells  in a table, or data used to construct a graph)
    3.  Click OK to accept your selections or Cancel to cancel the copy request.
                                           143

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  Copy To
  0 Clipboard

  OFile
      Copy As
      0 Bitmap
      O Metafile
      O Data (Text)
      OK
Cancel
Help
Figure 10-3. Example of the Copy dialog.
                   144

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CHAPTER 11 - FILES USED BY SWMM
This section describes the various files that SWMM can utilize. They include: the project file, the
report and output files, rainfall files, the climate file, calibration data files, time series files, and
interface files. The only file required to run SWMM is the project file;  the others are optional.
11.1    Project Files

A SWMM project file is a plain text file that contains all of the data used to describe a study area
and the options used to  analyze  it.  The file  is organized into sections, where each section
generally corresponds to a particular category of object used by SWMM. The contents of the file
can be viewed from within SWMM while it is open by selecting Project » Details from the
Main Menu. An existing project file can be opened by selecting File » Open from the Main
Menu and be saved by selecting File » Save (or File » Save As).

Normally  a SWMM user would not edit the project file directly, since SWMM's graphical user
interface can add, delete, or modify  a project's data and control settings. However, for large
projects where data currently reside in other electronic formats, such as CAD or GIS files, it may
be more expeditious to extract data  from these sources  and save it to  a formatted project file
before running SWMM. The format of the project file is described in detail in Appendix D of this
manual.

After a project file is saved to disk, a settings file will automatically be saved with it. This file has
the same name as the project file  except that its extension is .ini (e.g., if the project file were
named projectl.inp then its settings file would have the name projectl.ini). It contains various
settings used by SWMM's graphical user interface, such as map display options, legend colors
and intervals,  object default values, and calibration file information. Users should  not edit  this
file. A SWMM project will still load and run even if the settings file is missing.
11.2    Report and Output Files

The report file is  a plain text file created after every SWMM run that contains a status report on
the results of a run. It can be viewed by selecting Report » Status from the main menu. If the
run was unsuccessful it will contain a list of error messages.  For a successful run it will contain:
    •    the mass  continuity  errors for runoff quantity and quality as well as for flow and water
        quality routing,

    •    summary results tables for all drainage system nodes and links, and
    •    information about the time step size and iterations required when Dynamic Wave routing
        analyses are performed.

The output file is a binary file that contains the numerical results from a successful SWMM run.
This file is used by SWMM's user interface  to interactively create time series plots and tables,
profile plots, and statistical analyses of a simulation's results.
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Whenever a successfully run project is either saved or closed, the report and output files are saved
with the same name as the project file, but with extensions of .rpt and .out.  This will happen
automatically if the program preference Prompt to Save Results is turned off (see Section 4.9).
Otherwise the user is asked if the current results should be saved or not. If results are saved then
the next time the project is opened, the results from these files will automatically be available for
viewing.
11.3    Rainfall Files

SWMM's rain gage objects can utilize rainfall data stored in external rainfall files. The program
currently recognizes the following formats for storing such data:
    •    DSI-3240 and related formats which record hourly rainfall at U.S. National Weather
        Service (NWS) and Federal Aviation Agency stations,  available online from the National
        Climatic Data Center (NCDC) at www.ncdc.noaa.gov/oa/ncdc.html.

    •    DSI-3260 and related formats which record fifteen minute rainfall at NWS stations, also
        available online from NCDC.
    •    HLY03 and HLY21  formats for hourly rainfall  at Canadian stations, available online
        from Environment Canada at www.climate.weatheroffice.ec.gc.ca.
    •    FIF21 format for fifteen minute rainfall at Canadian stations, also available online from
        Environment Canada.
    •    a standard user-prepared format where each line of the file contains the station ID, year,
        month,  day, hour, minute, and non-zero precipitation reading,  all separated by one or
        more spaces.

An excerpt from a sample user-prepared Rainfall file is as follows:

    STA01   2004    6    12   00   00    0.12
    STA01   2004    6    12   01   00    0.04
    STA01   2004    6    22   16   00    0.07

When a rain gage is designated as receiving its rainfall data from a file, the user must supply the
name of the file and the name of the recording station referenced in the file. For the standard user-
prepared format, the rainfall type (e.g., intensity or volume), recording time interval,  and depth
units must also be supplied as rain gage properties. For the other file types these properties are
defined by their respective file format and are automatically recognized by SWMM.
11.4   Climate Files

SWMM can use an external climate file that contains daily air temperature, evaporation, and wind
speed data. The program currently recognizes the following formats:
    •   A DSI-3200 or DSI-3210 file available from the National Climatic Data Center at
       www.ncdc.noaa.gov/oa/ncdc.html.
    •   Canadian climate files available from Environment Canada at
       www.climate.weatheroffice.ec.gc.ca.
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    •   A user-prepared climate file where each line contains a recording station name, the year,
       month, day, maximum temperature, minimum temperature, and optionally, evaporation
       rate, and wind speed. If no data are available for any of these items on a given date, then
       an asterisk should be entered as its value.
When a climate  file  has days  with missing values, SWMM will use the  value from the most
recent previous day with a recorded value.
 ''T'1
 V    For a user-prepared climate file,  the data must be in the same units as the project being
       analyzed. For US units, temperature is in degrees F, evaporation  is in inches/day, and
       wind speed is in miles/hour. For metric units, temperature is in degrees C, evaporation is
       in mm/day, and wind speed is  in km/hour.
11.5   Calibration Files
Calibration files contain measurements of variables at one or more locations that can be compared
with simulated values in Time Series Plots. Separate files can be used for each of the following:
    •  Subcatchment Runoff
    •  Subcatchment Groundwater Flow
    •  Subcatchment Groundwater Elevation
    •  Subcatchment Snow Pack Depth
    •  Subcatchment Pollutant Washoff
    •  Node Depth
    •  Node Lateral Inflow
    •  Node Flooding
    •  Node Water Quality
    •  Link Flow
Calibration files are registered to a project by selecting Project» Calibration Data from the
main menu (see Section 5.5).
The format of the file is as follows:
    l.  The name of the first object with calibration data is entered on a single line.
    2.  Subsequent lines contain the following recorded measurements for the object:
           •  measurement date (month/day/year, e.g., 6/21/2004) or  number  of whole  days
              since the start of the simulation
           •  measurement time  (hours:minutes) on the measurement date or  relative to the
              number of elapsed days
           •  measurement value  (for pollutants, a value is required for each pollutant).
    3.  Follow the same sequence for any additional objects.
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An excerpt from an example calibration file is shown below. It contains flow values for two
conduits: 1030 and 1602. Note that a semicolon can be used to begin a comment. In this example,
elapsed time rather than the actual measurement date was used.

                  ;Flows  for  Selected Conduits
                  ;Conduit   Days    Time    Flow
1030
0
0
0
0
0
1602
0
0
0
0

0
0
0
1
1

0
0
1
1

15
30
45
00
15

15
30
00
15

0
0
23.88
94.58
115.37

5.76
38.51
67.93
68.01
11.6   Time Series Files

Time  series files are  external text files that contain data for SWMM's  time  series objects.
Examples of time  series  data include rainfall, evaporation, inflows to nodes of the drainage
system, and water stage at outfall boundary nodes. The file must be created and edited outside of
SWMM,  using a text editor or spreadsheet program. A time series file can be linked to a specific
time series object using SWMM's Time Series Editor.

The format of a time series file consists of one time series value per line. Comment lines can be
inserted anywhere in the file as long as they begin with a semicolon. Time series values can either
be in date / time / value format or in time / value format, where each entry is separated by one or
more  spaces or tab characters.  For the date / time / value  format, dates are  entered  as
month/day/year (e.g., 7/21/2004) and times  as  24-hour military time (e.g., 8:30 pm is 20:30).
After the first date, additional dates need only be entered whenever a new day occurs. For the
time /  value format, time can either be decimal hours  or military time  since the start of a
simulation (e.g.,  2  days, 4 hours and  20 minutes can be entered as either 52.333 or 52:20). An
example of a time series file is shown below:
; Rainfall
07/01/2003




07/06/2003



Data
00
00
00
00
01
14
14
15
18
for
00
15
30
45
00
30
45
00
15
Gage Gl
0.00000
0.03200
0.04800
0.02400
0.0100
0.05100
0.04800
0.03000
0.01000
                                          148

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        In earlier releases of SWMM 5, a time series file was required to have two header lines of
        descriptive text at the start of the file that did not have to begin with the semicolon
        comment character. These files can still be used as long as they are modified by inserting
        a semicolon at the front of the first two lines.
        When preparing rainfall time series files, it is only necessary to enter periods with non-
        zero rainfall  amounts. SWMM interprets  the rainfall value as a constant value lasting
        over the recording interval specified for the rain gage which utilizes the time series. For
        all other types of time series, SWMM uses interpolation to estimate values at times that
        fall in between the recorded values.
11.7    Interface Files

SWMM can use several different kinds of interface files that contain either externally imposed
inputs (e.g., rainfall or infiltration/inflow hydrographs) or the results of previously run analyses
(e.g., runoff or routing results). These files can help speed up simulations, simplify comparisons
of different loading scenarios, and allow large study areas to be broken up into smaller areas that
can be  analyzed individually.  The different types of interface files that are currently available
include:
    •   rainfall interface file
    •   runoff interface file
    •   hot start file
    •   RDII interface file
    •   routing interface files
Consult Section 8.1, Setting Simulation Options, for instructions on how to specify interface files
for use as input and/or output in a simulation.


Rainfall and Runoff Files

The rainfall and  runoff interface files are binary files  created internally by SWMM that can be
saved and reused from one analysis to the next.

The rainfall interface file collates a series of separate rain gage files into a single rainfall data file.
Normally a temporary  file of this type is created for every SWMM analysis  that uses external
rainfall data files and is then deleted after the analysis is completed. However, if the same rainfall
data are being used with many different analyses, requesting SWMM to save the rainfall interface
file after the first run and then reusing this file in subsequent runs can save computation time.

 (I"'1
 &     The rainfall interface file should not be confused with a rainfall data file. The latter is an
        external text file that provides rainfall time series data for a single rain gage. The former
        is a binary file created  internally by  SWMM that processes all  of the rainfall data files
        used by a project.
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The runoff interface file can be used to save the runoff results generated from a simulation run. If
runoff is not affected in future runs, the user can request that SWMM use this interface file to
supply runoff results without having to repeat the runoff calculations again.


Hot Start Files

Hot start files are binary files created by SWMM that save the current state of the study area's
groundwater and conveyance system at the end of a run. The following information is saved to
the file:
    •   the unsaturated zone moisture content and water table elevation for each subcatchment
       that has a groundwater zone defined for it
    •   the water depth and concentration of each pollutant at each node of the system
    •   the flow rate and concentration of each pollutant in each link of the system.
The hot start file saved after a run can be used to  define the initial  conditions for a subsequent
run.

Hot start files can be used to avoid the initial numerical instabilities that sometimes occur under
Dynamic Wave routing. For this purpose they are typically generated by imposing a constant set
of base flows (for  a natural channel network)  or set of dry weather sanitary flows (for a sewer
network) over some startup period of time. The resulting hot start file from this run is then used to
initialize a subsequent run where the inflows  of real interest are imposed.

It is also possible to both use  and save a hot start file in a single run,  starting off the run with one
file and  saving the ending results to another.  The resulting file can then  serve as the initial
conditions for a subsequent run  if need be.  This technique can be used to divide up extremely
long continuous simulations into  more manageable pieces.

Aside from using the project's Analysis Options to create a hot start file, one can also use the File
» Export » Hot Start File Main Menu command to save the results of a current run at any
particular time period to a hot start file. However, in this case only the results for nodes and links
will be saved and not those for groundwater.


RDM Files

The  RDII   interface  file is a  text file that contains a  time series of  rainfall-dependent
infiltration/inflow flows for a specified set of drainage system nodes. This file can be generated
from a previous SWMM run when  Unit  Hydrographs and nodal RDII inflow data  have been
defined for the project, or it can be created outside of SWMM using some other source of RDII
data (e.g., through measurements or output from a different computer program). The format of the
file is  the same as that of the routing interface file discussed below, where Flow is the only
variable contained in the file.


Routing Files

A  routing  interface  file stores  a  time series of  flows  and pollutant  concentrations that  are
discharged from the outfall nodes of drainage system model. This file can serve as the source of
inflow to another drainage  system model that is connected at the outfalls of the first system. A
Combine utility is available on the File menu that will combine pairs of routing interface files into
a single interface file. This  allows very large systems to be broken into smaller sub-systems that
                                           150

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can be analyzed separately and linked together through the routing interface file. Figure 11-1
below illustrates this concept.
                                        C ombine
                               outl .dat + out2.dat» inp3. dat
     Figure 11-1. Example of using the Combine utility to merge Routing files together.
A single SWMM run can utilize an outflows routing file to save results generated at a system's
outfalls, an inflows routing file to supply hydrograph and pollutograph inflows at selected nodes,
or both.

RDM / Routing File Format
RDII  interface files and routing interface files have the same text format:
    1. the first line contains the keyword "SWMM5" (without the quotes)
    2. a line of text that describes the file (can be blank)
    3. the time step used for all inflow records (integer seconds)
    4. the number of variables stored in the file, where the first variable must always be flow
       rate
    5. the name and units of each variable (one per line), where flow rate is the first variable
       listed and is always named FLOW
    6. the number of nodes with recorded inflow data
    7. the name of each node (one per line)
    8. a line of text that provides column headings for the data to follow (can be blank)
    9. for each node at each time step, a line with:
       •   the name of the node
       •   the date (year, month, and day separated by spaces)
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       •   the time of day (hours, minutes, and seconds separated by spaces)
       •   the flow rate followed by the concentration of each quality constituent

Time periods with no values at any node can be skipped. An  excerpt from an RDII / routing
interface file is shown below.

             SWMM5
             Example File
             300
             1
             FLOW CFS
             2
             Nl
             N2
             Node Year Mon Day Hr Min Sec Flow
             Nl    2002  04  01   00 20  00  0.000000
             N2    2002  04  01   00 20  00  0.002549
             Nl    2002  04  01   00 25  00  0.000000
             N2    2002  04  01   00 25  00  0.002549
                                     152

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CHAPTER 12 - USING ADD-IN TOOLS
SWMM 5 has the ability to launch external applications from its graphical user interface that can
extend its capabilities.  This section describes how such tools can be registered and share  data
with SWMM 5.


12.1   What Are Add-In Tools

Add-in tools are  third party  applications  that users can add to the  Tools menu of the main
SWMM menu bar and be launched while SWMM is still running. SWMM can interact with these
applications to a limited degree by exchanging data through its pre-defined files  (see Chapter 11)
or through the Windows clipboard. Add-in tools can provide additional modeling capabilities to
what SWMM already offers. Some examples of useful add-ins might include:
    •   a tool that performs a statistical analysis of long-term rainfall data prior to adding it to a
       SWMM rain gage,

    •   an external spreadsheet program that would facilitate the editing of a SWMM data set,
    •   a unit hydrograph estimator program that would derive the R-T-K parameters for a set of
       RDII unit hydrographs which could  then be copied and pasted directly into SWMM's
       Unit Hydrograph Editor,

    •   a  post-processor program that uses SWMM's hydraulic results to compute suspended
       solids removal through a storage unit,
    •   a  third-party dynamic flow routing  program used  as  a substitute  for SWMM's  own
       internal procedure.

Figure 12-1 shows what the Tools menu  might look like after several add-in  tools have  been
registered with it.  The Configure Tools option is used to add, delete, or modify add-in tools. The
options below this are the individual tools that have been made available (by this particular user)
and can be launched by selecting them from the menu.
      OSWMM 5
File  Edit
  D tf
               View
       Data   Map
           Title/Notes A.
           Options
           Climatology
        ffl  Hydrology
        l±j  Hydraulics
        ii!  Quality
                         OStudy
)ls  Window  Help

 Program Preferences...
 Map Display Options...
                               Configure Tools.
                               SWMM 4 Converter
                               Spreadsheet Editor
                                      n  x
                           Figure 12-1.  SWMM's Tools menu.
                                           153

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12.2   Configuring Add-In Tools

To configure one's personal collection of add-in tools, select Configure Tools from the Tools
menu. This will bring up the Tool Options dialog as shown in Figure 12-2. The dialog lists the
currently available tools and has command buttons for adding a new tool and for deleting or
editing an existing tool. The up and down arrow buttons are used to change the order in which the
registered tools are listed on the Tools menu.
                      Tool Options
                        Tools
                        iSWMM 4 Converter
                        Spreadsheet Editor
                                                           Add
                                                          Delete
                                                           Edit
                                                          Close
                                                          Help
                          Figure 12-2.  The Tools Options dialog.
Whenever the Add or Edit button is clicked on this dialog a Tool Properties dialog will appear as
shown in Figure 12-3. This dialog is used to describe the properties of the new tool being added
or the existing tool being edited.
                                           154

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            Tool Properties
              Tool Name:


              Program:

              Working
              Directory:

              Parameters:
              Macros:
                            Spreadsheet Editor
CAProgram Files\Microsoft Office\0ffice1 (MXCELEX
SINPFILE
SPROJDIR
SSWMMDIR
$INPFILE
$RPTFILE
SOUTFILE
SRIFFILE

Project directory
SWMM directory
SWMM input file
SWMM report file
SWMM output file
SWMM runoff interface file
JT+"

                           0 Disable SWMM while executing

                           0 Update SWMM after closing
                              OK
                             Help
                         Figure 12-3. The Tool Properties dialog.


The data entry fields of the Tool Properties dialog consist of the following:

Tool Name
This is the name to be used for the tool when it is displayed in the Tools Menu.

Program

Enter the full path name to the  program that will be launched when the tool is selected. You can
click the I—' button to bring up a standard Windows file selection dialog from which you can
search for the tool's executable file name.

Working Directory
This field contains the name of the directory that will be used as the working directory when the
                                  Gal
tool is launched. You can click the _' button to bring up a standard directory selection dialog
from which you  can search for the  desired directory. You can also enter the macro  symbol
$PROJDIR to utilize the current SWMM project's directory or $SWMMDIR to use the directory
where the SWMM 5 executable resides. Either of these macros can also be inserted into the
Working Directory field by selecting its name  in the list  of macros provided on the dialog and
then clicking the —  button. This field can be left blank, in which case the system's current
directory will be used.
                                            155

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Parameters
This field contains the list of command line arguments that the tool's executable program expects
to see when it is launched.  Multiple parameters can be entered as long as they are separated by
spaces. A number of special macro symbols have been pre-defined, as listed in the Macros list
box of the dialog, to simplify the process of listing the command line parameters. When one of
these macro symbols is inserted into the list of parameters, it will be expanded to its true value
when the tool is launched. A specific macro symbol can either be typed into the Parameters field
or be selected from the Macros list (by clicking on it) and then added to the parameter list by

clicking the    button. The available macro symbols and their meanings are defined in Table
12-1 below.

As an example of how the macro expansion works,  consider the entries in the  Tool Properties
dialog shown in Figure 12-3. This Spreadsheet Editor tool wants to launch Microsoft Excel and
pass it the name of the SWMM input data file to be opened by Excel. SWMM will issue the
following command line to do this

  c:\Program  Files\Microsoft  Office\OfficelO\EXCEL.EXE $INPFILE

where the  string SINPFILE is replaced by the name of a temporary file that SWMM creates
internally which will contain the current project's data.
Table 12-1. Macros Used as Command Line Parameters for External Tools
MACRO SYMBOL
$PROJDIR
$SWMMDIR
$INPFILE
$RPTFILE
$OUTFILE
$RIFFILE
EXPANDS TO
The directory where the current SWMM project file resides.
The directory where the SWMM 5 executable is installed.
The name of a temporary file containing the current project's data that is
created just before the tool is launched.
The name of a temporary file that is created just before the tool is
launched and can be displayed after the tool closes by using the Report
» Status command from the main SWMM menu.
The name of a temporary file to which the tool can write simulation
results in the same format used by SWMM 5, which can then be displayed
after the tool closes in the same fashion as if a SWMM run were made.
The name of the Runoff Interface File, as specified in the Interface Files
page of the Simulation Options dialog, to which runoff simulation results
were saved from a previous SWMM run (see Sections 8. 1 and 11.7).
                                         156

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Disable SWMM while executing

Check this option if SWMM  should be minimized and disabled while the tool is executing.
Normally you will need to employ this option if the tool produces a modified input file or output
file, such as when the $INPFILE or $OUTFILE macros are used as command line parameters.
When this option is enabled, SWMM's main window will be minimized and will not respond to
user input until the tool is terminated.

Update SWMM after closing
Check this option if SWMM should be updated after the tool finishes executing. This option can
only be selected if the option to disable SWMM while the tool  is executing was first selected.
Updating can occur in two ways. If the $INPFILE macro was used as a command line parameter
for the tool and the corresponding temporary input file produced  by SWMM was updated by the
tool, then the current project's data will be replaced with the  data contained in the  updated
temporary input file. If the $OUTFILE macro was used as a command line parameter, and its
corresponding file is found to contain a valid set of output  results after the  tool closes,  then the
contents of this file will be used to display simulation results within the SWMM workspace.

Generally speaking, the suppliers of third-party tools will provide instructions  on what settings
should be used in the Tool Properties dialog to properly register their tool with SWMM.
                                           157

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               158

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APPENDIX A - USEFUL TABLES
A.1   Units of Measurement
PARAMETER
Area (Subcatchment)
Area (Storage Unit)
Area (Ponding)
Capillary Suction
Concentration
Decay Constant (Infiltration)
Decay Constant (Pollutants)
Depression Storage
Depth
Diameter
Discharge Coefficient
Orifice
Weir
Elevation
Evaporation
Flow
Head
Hydraulic Conductivity
Infiltration Rate
Length
Manning's n
Pollutant Buildup
Rainfall Intensity
Rainfall Volume
Slope (Subcatchments)
Slope (Cross Section)
Street Cleaning Interval
Volume
Width
US CUSTOMARY
acres
square feet
square feet
inches
mg/L (milligrams/liter)
ug/L (micrograms/liter)
Count/L (counts/liter)
1 /hours
I/days
inches
feet
feet
dimensionless
CFS/footn
feet
inches/day
CFS (cubic feet / second)
GPM (gallons / minute)
MGD (million gallons/day)
feet
inches/hour
inches/hour
feet
seconds/meter
mass/length
mass/acre
inches/hour
inches
percent
rise/run
days
cubic feet
feet
SI METRIC
hectares
square meters
square meters
millimeters
mg/L
ug/L
Count/L
1 /hours
I/days
millimeters
meters
meters
dimensionless
CMS/meter"
meters
millimeters/day
CMS (cubic meters/second)
LPS (liters/second)
MLD (million liters/day)
meters
millimeters/hour
millimeters/hour
meters
seconds/meter
mass/length
mass/hectare
millimeters/hour
millimeters
percent
rise/run
days
cubic meters
meters
                            159

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A.2     Soil Characteristics
Soil Texture Class
Sand
Loamy Sand
Sandy Loam
Loam
Silt Loam
Sandy Clay Loam
Clay Loam
Silty Clay Loam
Sandy Clay
Silty Clay
Clay
K
4.74
1.18
0.43
0.13
0.26
0.06
0.04
0.04
0.02
0.02
0.01
*F
1.93
2.40
4.33
3.50
6.69
8.66
8.27
10.63
9.45
11.42
12.60
$
0.437
0.437
0.453
0.463
0.501
0.398
0.464
0.471
0.430
0.479
0.475
FC
0.062
0.105
0.190
0.232
0.284
0.244
0.310
0.342
0.321
0.371
0.378
WP
0.024
0.047
0.085
0.116
0.135
0.136
0.187
0.210
0.221
0.251
0.265
        K  = saturated hydraulic conductivity, in/hr
        *F  = suction head, in.
        <|>  = porosity, fraction
        FC = field capacity, fraction
        WP= wilting point, fraction

        Source: Rawls, W.J. et al, (1983). J. Hyd. Engr., 109:1316.
                                            160

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A.3     NRCS Hydrologic Soil Group Definitions
        Group
Meaning
  Saturated
  Hydraulic
Conductivity
   (in/hr)
          B
                 Low runoff potential. Soils having high infiltration rates
                 even when thoroughly wetted and consisting chiefly of
                 deep, well to excessively drained sands or gravels.
                                                            >0.45
Soils having moderate infiltration rates when thoroughly
wetted and consisting chiefly of moderately deep to deep,
moderately well to well-drained soils with moderately fine
to moderately coarse textures. E.g., shallow loess, sandy
loam.
 0.30-0.15
          C
Soils having slow infiltration rates when thoroughly
wetted and consisting chiefly of soils with a layer that
impedes downward movement of water, or soils with
moderately fine to fine textures. E.g., clay loams, shallow
sandy loam.
 0.15-0.05
          D
High runoff potential.  Soils having very slow infiltration
rates when thoroughly wetted and consisting chiefly of
clay soils with a high swelling potential, soils with a
permanent high water table, soils with a clay-pan or clay
layer at or near the surface, and shallow soils over nearly
impervious material.
 0.05 - 0.00
                                           161

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A.4    SCS Curve Numbers1

Land Use Description
Hydrologic Soil Group
A
B
C
Cultivated land
Without conservation treatment 72 81
With conservation treatment 62 71
Pasture or range land
Poor condition
Good condition
Meadow
Good condition

68
39

30

79
61

58
Wood or forest land
Thin stand, poor cover, no mulch 45 66
Good cover2 25 55
Open spaces, lawns, parks, golf
courses, cemeteries, etc.
Good condition: grass cover on






75% or more of the area 39 61
Fair condition: grass cover on
50-75% of the area
Commercial and business areas (85%

49
89

69
92
impervious)
Industrial districts (72% impervious)
81
88
Residential3
Average lot size (% Impervious4)
1/8 ac or less (65)
1/4 ac (38)
1/3 ac (30)
1/2 ac (25)
1 ac (20)
Paved parking lots, roofs, driveways,
etc.5
77
61
57
54
51
98

85
75
72
70
68
98

Streets and roads
Paved with curbs and storm sewers5 98 98
Gravel 76 85
Dirt
72
82
88
78

86
74

71

77
70



74

79
94

91


90
83
81
80
79
98


98
89
87
D

91
81

89
80

78

83
77



80

84
95

93


92
87
86
85
84
98


98
91
89
       5.
Antecedent moisture condition II; Source: SCS Urban Hydrology for Small
Watersheds, 2nd Ed., (TR-55), June 1986.
Good cover is protected from grazing and litter and brush cover soil.
Curve numbers are computed assuming that the runoff from the house and driveway
is directed toward the street with a minimum of roof water directed to lawns where
additional infiltration could occur.
The remaining pervious areas (lawn) are considered to be in good pasture condition
for these curve numbers.
In some warmer climates of the country a curve number of 95 may be used.
                                         162

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A.5    Depression Storage
       Impervious surfaces   0.05 - 0.10 inches
       Lawns
0.10-0.20 inches
       Pasture
0.20 inches
       Forest litter
0.30 inches
       Source: ASCE, (1992). Design & Construction of Urban Stormwater Management
              Systems, New York, NY.
A.6    Manning's n - Overland Flow
Surface
Smooth asphalt
Smooth concrete
Ordinary concrete lining
Good wood
Brick with cement mortar
Vitrified clay
Cast iron
Corrugated metal pipes
Cement rubble surface
Fallow soils (no residue)
Cultivated soils
Residue cover < 20%
Residue cover > 20%
Range (natural)
Grass
Short, prarie
Dense
Bermuda grass
Woods
Light underbrush
Dense underbrush
n
0.011
0.012
0.013
0.014
0.014
0.015
0.015
0.024
0.024
0.05
0.06
0.17
0.13
0.15
0.24
0.41
0.40
0.80
    Source: McCuen, R. et al. (1996), Hydrology, FHWA-SA-96-067, Federal Highway
          Administration, Washington, DC
                                        163

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A.7    Manning's n - Closed Conduits
Conduit Material
Asbestos-cement pipe
Brick
Manning n
0.011
0.013
Cast iron pipe
- Cement-lined & seal coated 0.01 1
Concrete (monolithic)
- Smooth forms
- Rough forms
Concrete pipe
Corrugated-metal pipe
(1/2-in. x2-2/3-in. corrugations)
- Plain
- Paved invert
- Spun asphalt lined
Plastic pipe (smooth)
Vitrified clay
- Pipes
- Liner plates
0.012
0.015
0.011
0.022
0.018
0.011
0.011
0.011
0.013
-0.015
-0.017
-0.015
-0.014
-0.017
-0.015
- 0.026
- 0.022
-0.015
-0.015
-0.015
-0.017
   Source: ASCE (1982). Gravity Sanitary Sewer Design and Construction, ASCE Manual of
          Practice No. 60, New York, NY.
                                       164

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A.8    Manning's n- Open Channels
Channel Type
Lined Channels
- Asphalt
- Brick
- Concrete
- Rubble or riprap
- Vegetal
Excavated or dredged
- Earth, straight and uniform
- Earth, winding, fairly uniform
-Rock
- Unmaintained
Natural channels (minor streams,
top width at flood stage < 100 ft)
Manning n

0.013
0.012
0.011
0.020
0.030
-0.017
-0.018
- 0.020
- 0.035
-0.40

0.020
0.025
0.030
0.050
- 0.030
- 0.040
- 0.045
-0.140

- Fairly regular section 0.030
- 0.070
       - Irregular section with pools
0.040-0.100
    Source: ASCE (1982). Gravity Sanitary Sewer Design and Construction, ASCE Manual of
          Practice No. 60, New York, NY.
A.9    Water Quality Characteristics of Urban Runoff
Constituent
TSS (mg/L)
BOD (mg/L)
COD (mg/L)
Total P (mg/L)
Soluble P (mg/L)
TKN (mg/L)
NO2/NO3-N (mg/L)
Total Cu (ug/L)
Total Pb (ug/L)
Total Zn (ug/L)
Event Mean
Concentrations
180-548
12- 19
82- 178
0.42-0.88
0.15-0.28
1.90-4.18
0.86-2.2
43- 118
182 - 443
202 - 633
    Source: U.S. Environmental Protection Agency. (1983). Results of the Nationwide Urban
          Runoff Program (NURP), Vol. I, NTIS PB 84-185552), Water Planning Division,
          Washington, DC.
                                        165

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A.10   Culvert Code Numbers

       Circular Concrete
       1   Square edge with head-wall
       2   Groove end with headwall
       3   Groove end projecting

       Circular Corrugated Metal Pipe
       4   Headwall
       5   Mitered to slope
       6   Projecting

       Circular Pipe, Beveled Ring Entrance
       7   45 deg. bevels
       8   33.7 deg. bevels

       Rectangular Box; Flared Wingwalls
       9   30-75 deg. wingwall flares
       10  90 or 15 deg. wingwall flares
       110 deg. wingwall flares (straight sides)

       Rectangular Box;Flared Wingwalls and Top Edge Bevel:
       12  45 deg flare; 0.43D top edge bevel
       13  18-33.7 deg. flare; 0.083D top edge bevel

       Rectangular Box, 90-deg Headwall, Chamfered / Beveled Inlet Edges
       14  chamfered 3/4-in.
       15  beveled 1/2-in/ft at 45 deg (1:1)
       16  beveled 1-in/ft at 33.7 deg (1:1.5)

       Rectangular Box, Skewed Headwall, Chamfered / Beveled Inlet Edges
       17  3/4" chamfered edge, 45 deg skewed headwall
       18  3/4" chamfered edge, 30 deg skewed headwall
       19  3/4" chamfered edge, 15 deg skewed headwall
       20  45 deg beveled edge, 10-45  deg skewed headwall

       Rectangular Box, Non-offset Flared Wingwalls, 3/4" Chamfer at Top of Inlet
       21  45 deg (1:1) wingwall flare
       22  8.4 deg (3:1) wingwall flare
       23  18.4 deg (3:1) wingwall flare, 30 deg inlet skew

       Rectangular Box, Offset Flared Wingwalls, Beveled Edge at Inlet Top
       24  45 deg (1:1) flare, 0.042D top edge bevel
       25  33.7 deg (1.5:1) flare, 0.083D top edge bevel
       26  18.4 deg (3:1) flare, 0.083D top edge bevel

       Corrugated Metal Box
       27  90 deg headwall
       28  Thick wall projecting
       29  Thin wall projecting
                                        166

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Horizontal Ellipse Concrete
30  Square edge with headwall
31  Grooved end with headwall
32  Grooved end projecting

Vertical Ellipse Concrete
33  Square edge with headwall
34  Grooved end with headwall
35  Grooved end projecting

Pipe Arch, 18" Corner Radius, Corrugated Metal
36  90 deg headwall
37  Mitered to slope
38  Projecting

Pipe Arch, 18" Corner Radius, Corrugated Metal
39  Projecting
40  No bevels
41  33.7 deg bevels

Pipe Arch, 31" Corner Radius,Corrugated Metal
42  Projecting
43  No bevels
44  33.7 deg. bevels

Arch, Corrugated Metal
45  90 deg headwall
46  Mitered to slope
47  Thin wall projecting

Circular Culvert
48  Smooth tapered inlet throat
49  Rough tapered inlet throat

Elliptical Inlet Face
50  Tapered inlet, beveled edges
51  Tapered inlet, square edges
52  Tapered inlet, thin edge projecting

Rectangular
53  Tapered inlet throat

Rectangular Concrete
54  Side tapered, less favorable edges
55  Side tapered, more favorable edges
56  Slope tapered, less favorable edges
57  Slope tapered, more favorable edges
                                  167

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A.11   Culvert Entrance Loss Coefficients

       Type of Structure and Design of Entrance               Coefficient

       • Pipe, Concrete
           Projecting from fill, socket end (groove-end)               0.2
           Projecting from fill, sq. cut end                            0.5
           Headwall or headwall and wingwalls:
               Socket end of pipe (groove-end)                       0.2
               Square-edge                                         0.5
           Rounded (radius = D/12)                                 0.2
           Mitered to conform to fill slope                           0.7
           *End-Section conforming to fill slope                      0.5
           Beveled edges, 33.7 ° or 45 ° bevels                       0.2
           Side- or slope-tapered inlet                               0.2

       • Pipe or Pipe-Arch. Corrugated Metal
           Projecting from fill (no headwall)                         0.9
           Headwall or headwall and wingwalls square-edge           0.5
           Mitered to conform to fill slope, paved or unpaved slope     0.7
           *End-Section conforming to fill slope                      0.5
           Beveled edges, 33.7 ° or 45 ° bevels                       0.2
           Side- or slope-tapered inlet                               0.2

       • Box, Reinforced Concrete
           Headwall parallel to embankment (no wingwalls):
               Square-edged on 3 edges                             0.5
               Rounded on 3 edges to radius of D/12 or B/12
                  or beveled edges on 3 sides                       0.2
           Wingwalls at 30 ° to 75 ° to barrel:
               Square-edged at crown                               0.4
               Crown edge rounded to radius of D/12:
               or beveled top edge                                  0.2
           Wingwall at 10 ° to 25 ° to barrel:
               Square-edged at crown                               0.5
           Wingwalls parallel (extension of sides):
               Square-edged at crown                               0.7
               Side- or slope-tapered inlet                            0.2

       *Note: "End Sections conforming to fill slope," made  of either metal or concrete, are the
       sections commonly available from manufacturers. From limited hydraulic tests they are
       equivalent in operation to a headwall in both inlet and outlet control. Some end sections,
       incorporating a closed taper in their design have a superior hydraulic performance. These
       latter sections can be designed using the information given for the beveled inlet.

       Source: Federal Highway Administration (2005). Hydraulic Design of Highway Culverts,
               Publication No. FHWA-NHI-01-020.
                                          168

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APPENDIX B - VISUAL OBJECT PROPERTIES
B.1   Rain Gage Properties
Name
X-Coordinate
Y-Coordinate
Description
Tag
Rain Format
Rain Interval
Snow Catch
Factor
Data Source
TIME SERIES
- Series Name
DATA FILE
- File Name
- Station No.
- Rain Units
User-assigned rain gage name.
Horizontal location of the rain gage on the Study Area Map. If left
blank then the rain gage will not appear on the map.
Vertical location of the rain gage on the Study Area Map. If left
blank then the rain gage will not appear on the map.
Click the ellipsis button (or press Enter) to edit an optional
description of the rain gage.
Optional label used to categorize or classify the rain gage.
Format in which the rain data are supplied:
INTENSITY: each rainfall value is an average rate in inches/hour
(or mm/hour) over the recording interval,
VOL UME: each rainfall value is the volume of rain that fell in the
recording interval (in inches or millimeters),
CUMULATIVE: each rainfall value represents the cumulative
rainfall that has occurred since the start of the last series of non-
zero values (in inches or millimeters).
Recording time interval between gage readings in either decimal
hours or hours:minutes format.
Factor that corrects gage readings for snowfall.
Source of rainfall data; either TIMESERIES for user-supplied
time series data or FILE for an external data file.

Name of time series with rainfall data if Data Source selection
was TIMESERIES, leave blank otherwise (double-click to edit
the series).

Name of external file containing rainfall data.
Recording gage station number.
Depth units (IN or MM) for rainfall values in the file.
                           169

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B.2   Subcatchment Properties
Name
X-Coordinate
Y-Coordinate
Description
Tag
Rain Gage
Outlet
Area
Width
% Slope
% Imperv
N-Imperv
N-Perv
Dstore-Imperv
Dstore-Perv
% Zero-Imperv
Subarea Routing
User-assigned subcatchment name.
Horizontal location of the subcatchment's centroid on the Study
Area Map. If left blank then the subcatchment will not appear on
the map.
Vertical location of the subcatchment's centroid on the Study Area
Map. If left blank then the subcatchment will not appear on the
map.
Click the ellipsis button (or press Enter) to edit an optional
description of the subcatchment.
Optional label used to categorize or classify the subcatchment.
Name of the rain gage associated with the subcatchment.
Name of the node or subcatchment which receives the
subcatchment's runoff.
Area of the subcatchment (acres or hectares).
Characteristic width of the overland flow path for sheet flow
runoff (feet or meters). An initial estimate of the characteristic
width is given by the subcatchment area divided by the average
maximum overland flow length. The maximum overland flow
length is the length of the flow path from the the furthest drainage
point of the subcatchment before the flow becomes channelized.
Maximum lengths from several different possible flow paths
should be averaged. These paths should reflect slow flow, such as
over pervious surfaces, more than rapid flow over pavement, for
example. Adjustments should be made to the width parameter to
produce good fits to measured runoff hydrographs.
Average percent slope of the subcatchment.
Percent of land area which is impervious.
Manning's n for overland flow over the impervious portion of the
subcatchment (see Section A. 6 for typical values).
Manning's n for overland flow over the pervious portion of the
subcatchment (see Section A. 6 for typical values).
Depth of depression storage on the impervious portion of the
subcatchment (inches or millimeters) (see Section A. 5 for typical
values).
Depth of depression storage on the pervious portion of the
subcatchment (inches or millimeters) (see Section A. 5 for typical
values).
Percent of the impervious area with no depression storage.
Choice of internal routing of runoff between pervious and
impervious areas:
IMPERV. runoff from pervious area flows to impervious area,
PERV. runoff from impervious area flows to pervious area,
OUTLET, runoff from both areas flows directly to outlet.
                                    170

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Percent Routed
Infiltration
LID Controls
Groundwater
Snow Pack
Land Uses
Initial Buildup
Curb Length
Percent of runoff routed between subareas.
Click the ellipsis button (or press Enter) to edit infiltration
parameters for the subcatchment.
Click the ellipsis button (or press Enter) to edit the use of low
impact development controls in the subcatchment.
Click the ellipsis button (or press Enter) to edit groundwater flow
parameters for the subcatchment.
Name of snow pack parameter set (if any) assigned to the
subcatchment.
Click the ellipsis button (or press Enter) to assign land uses to the
subcatchment.
Click the ellipsis button (or press Enter) to specify initial
quantities of pollutant buildup over the subcatchment.
Total length of curbs in the subcatchment (any length units). Used
only when pollutant buildup is normalized to curb length.
171

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B.3    Junction Properties
Name
X-Coordinate
Y-Coordinate
Description
Tag
Inflows
Treatment
Invert El.
Max. Depth
Initial Depth
Surcharge Depth
Ponded Area
User-assigned junction name.
Horizontal location of the junction on the Study Area Map. If left
blank then the junction will not appear on the map.
Vertical location of the junction on the Study Area Map. If left
blank then the junction will not appear on the map.
Click the ellipsis button (or press Enter) to edit an optional
description of the junction.
Optional label used to categorize or classify the junction.
Click the ellipsis button (or press Enter) to assign external direct,
dry weather or RDII inflows to the junction.
Click the ellipsis button (or press Enter) to edit a set of treatment
functions for pollutants entering the node.
Invert elevation of the junction (feet or meters).
Maximum depth of junction (i.e., from ground surface to invert)
(feet or meters). If zero, then the distance from the invert to the
top of the highest connecting link will be used.
Depth of water at the junction at the start of the simulation (feet or
meters).
Additional depth of water beyond the maximum depth that is
allowed before the junction floods (feet or meters). This parameter
can be used to simulate bolted manhole covers or force main
connections.
Area occupied by ponded water atop the junction after flooding
occurs (sq. feet or sq. meters). If the Allow Ponding simulation
option is turned on, a non-zero value of this parameter will allow
ponded water to be stored and subsequently returned to the
conveyance system when capacity exists.
                                       172

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B.4    Outfall Properties
Name
X-Coordinate
Y-Coordinate
Description
Tag
Inflows
Treatment
Invert El.
Tide Gate
Type
Fixed Stage
Tidal Curve
Name
Time Series
Name
User-assigned outfall name.
Horizontal location of the outfall on the Study Area Map. If left
blank then the outfall will not appear on the map.
Vertical location of the outfall on the Study Area Map. If left
blank then the outfall will not appear on the map.
Click the ellipsis button (or press Enter) to edit an optional
description of the outfall.
Optional label used to categorize or classify the outfall.
Click the ellipsis button (or press Enter) to assign external direct,
dry weather or RDII inflows to the outfall.
Click the ellipsis button (or press Enter) to edit a set of treatment
functions for pollutants entering the node.
Invert elevation of the outfall (feet or meters).
YES - tide gate present to prevent backflow
NO - no tide gate present
Type of outfall boundary condition:
FREE: outfall stage determined by minimum of critical flow
depth and normal flow depth in the connecting conduit
NORMAL: outfall stage based on normal flow depth in
connecting conduit
FIXED: outfall stage set to a fixed value
TIDAL: outfall stage given by a table of tide elevation versus time
of day
TIMESERIES: outfall stage supplied from a time series of
elevations.
Water elevation for a FIXED type of outfall (feet or meters).
Name of the Tidal Curve relating water elevation to hour of the
day for a TIDAL outfall (double-click to edit the curve).
Name of time series containing time history of outfall elevations
for a TIMESERIES outfall (double-click to edit the series).
                                        173

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B.5    Flow Divider Properties
       Name
User-assigned divider name.
       X-Coordinate
       Y-Coordinate
       Description
Horizontal location of the divider on the Study Area Map. If left
blank then the divider will not appear on the map.
Vertical location of the divider on the Study Area Map. If left
blank then the divider will not appear on the map.
Click the ellipsis button (or press Enter) to edit an optional
description of the divider.
       Tag
Optional label used to categorize or classify the divider.
Inflows
Treatment
Click the ellipsis button (or press Enter) to
dry weather or RDII inflows to the divider
Click the ellipsis button (or press Enter) to
functions for pollutants entering the node.
assign external direct,
edit a set of treatment
       Invert El.
Invert elevation of the divider (feet or meters).
       Max. Depth

       Initial Depth
Maximum depth of divider (i.e., from ground surface to invert)
(feet or meters). See description for Junctions.
Depth of water at the divider at the start of the simulation (feet or
meters).
       Surcharge Depth
Additional depth of water beyond the maximum depth that is
allowed before the junction floods (feet or meters).
       Ponded Area
       Diverted Link
Area occupied by ponded water atop the junction after flooding
occurs (sq. feet or sq. meters). See description for Junctions.
Name of link which receives the diverted flow.
       Type
Type of flow divider. Choices are:
CUTOFF (diverts all inflow above a defined cutoff value),
OVERFLOW (diverts all inflow above the flow capacity of the
non-diverted link),
TABULAR (uses a Diversion Curve to express diverted flow as a
function of the total inflow),
WEIR (uses a weir equation to compute diverted flow).
       CUTOFF DIVIDER
      \  - Cutoff Flow     | Cutoff flow value used for a CUTOFF divider (flow units).
      [TABULAR DIVIDER~
        - Curve Name
Name of Diversion Curve used with a TABULAR divider
(double-click to edit the curve).
       WEIR DIVIDER
        - Min. Flow
Minimum flow at which diversion begins for a WEIR divider
(flow units).
        - Max. Depth
Vertical height of WEIR opening (feet or meters)
        - Coefficient
Product of WEIR's discharge coefficient and its length. Weir
coefficients are typically in the range of 2.65 to 3.10 per foot, for
flows in CFS.
                                          174

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B.6    Storage Unit Properties
Name
X-Coordinate
Y-Coordinate
Description
Tag
Inflows
Treatment
Invert El.
Max. Depth
Initial Depth
Ponded Area
Evap. Factor
Infiltration
Storage Curve
FUNCTIONAL
- Coeff.
- Exponent
- Constant
TABULAR
- Curve Name
User-assigned storage unit name.
Horizontal location of the storage unit on the Study Area Map. If
left blank then the storage unit will not appear on the map.
Vertical location of the storage unit on the Study Area Map. If left
blank then the storage unit will not appear on the map.
Click the ellipsis button (or press Enter) to edit an optional
description of the storage unit.
Optional label used to categorize or classify the storage unit.
Click the ellipsis button (or press Enter) to assign external direct,
dry weather or RDII inflows to the storage unit.
Click the ellipsis button (or press Enter) to edit a set of treatment
functions for pollutants entering the storage unit.
Elevation of the bottom of the storage unit (feet or meters).
Maximum depth of the storage unit (feet or meters).
Initial depth of water in the storage unit at the start of the
simulation (feet or meters).
Surface area occupied by ponded water atop the storage unit once
the water depth exceeds the maximum depth (sq. feet or sq.
meters). See description for Junctions .
The fraction of the potential evaporation from the storage unit's
water surface that is actually realized.
Click the ellipsis button (or press Enter) to supply a set of Green-
Ampt parameters that describe how water can infiltrate into the
native soil below the unit. See Section C.7 for a description of
these parameters, To disable any infiltration, make sure that these
parameters are blank.
Method of describing the geometric shape of the storage unit:
FUNCTIONAL uses the function
Area = A*(Depth)/"B + C
to describe how surface area varies with depth;
TABULAR uses a tabulated area versus depth curve.
In either case, depth is measured in feet (or meters) and surface
area in sq. feet (or sq. meters).

A-value in the functional relationship between surface area and
storage depth.
B-value in the functional relationship between surface area and
storage depth.
C-value in the functional relationship between surface area and
storage depth.

Name of the Storage Curve containing the relationship between
surface area and storage depth (double-click to edit the curve).
                                       175

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B.7    Conduit Properties
       Name
       Inlet Node
 User-assigned conduit name.
 Name of node on the inlet end of the conduit (which is normally
 the end at higher elevation).
       Outlet Node
 Name of node on the outlet end of the conduit (which is normally
 the end at lower elevation).
       Description
 Click the ellipsis button (or press Enter) to edit an optional
 description of the conduit.
       Tag
 Optional label used to categorize or classify the conduit.
       Shape
 Click the ellipsis button (or press Enter) to edit the geometric
 properties of the conduit's cross section.
       Max. Depth
       Length
 Maximum depth of the conduit's cross section (feet or meters).
[Conduit length (feet or meters).
       Roughness
       Inlet Offset
 Manning's roughness coefficient (see Section A.7 for closed
 conduit values or Section A.8 for open channel values).
 Depth or elevation of the conduit invert above the node invert at
 the upstream end of the conduit (feet or meters).
       Outlet Offset
       Initial Flow
 Depth or elevation of the conduit invert above the node invert at
 the downstream end of the conduit (feet or meters).
 Initial flow in the conduit (flow units).
       Maximum Flow
 Maximum flow allowed in the conduit (flow units) - use 0 or
 leave blank if not applicable.
       Entry Loss Coeff.    Head loss coefficient associated with energy losses at the entrance
                           of the conduit. For culverts, refer to Table All.
       Exit Loss Coeff.
 Head loss coefficient associated with energy losses at the exit of
 the conduit. For culverts, use a value of 1.0
       Avg. Loss Coeff.
 Head loss coefficient associated with energy losses along the
 length of the conduit.
       Flap Gate
  YES if a flap gate exists that prevents backflow through the
  conduit, or NO if no flap gate exists.
       Culvert Code
 Code number of inlet geometry if conduit is a culvert - leave
 blank otherwise. Culvert code numbers are listed in Table A10.
       NOTE:  Conduits and flow regulators (orifices, weirs, and
       outlets)  can be offset some distance  above the  invert of
       their connecting end  nodes.  There  are  two  different
       conventions available for specifying the location of these
       offsets. The Depth convention uses the offset distance from
       the node's invert (distance between © and © in the figure
       on the right). The Elevation convention uses the absolute
       elevation of the offset location (the elevation of point © in
       the figure). The choice of convention can be made on the
       Status Bar of SWMM's main window or on the Node/Link
       Properties page of the Project Defaults dialog.
                                           176

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B.8    Pump Properties
Name
Inlet Node
Outlet Node
Description
Tag
Pump Curve
Initial Status
Startup Depth
Shutoff Depth
User-assigned pump name.
Name of node on the inlet side of the pump.
Name of node on the outlet side of the pump.
Click the ellipsis button (or press Enter) to edit an optional
description of the pump.
Optional label used to categorize or classify the pump.
Name of the Pump Curve which contains the pump's operating
data (double-click to edit the curve). Use * for an Ideal pump.
Status of the pump (ON or OFF) at the start of the simulation.
Depth at inlet node when pump turns on (feet or meters).
Depth at inlet node when pump shuts off (feet or meters).
B.9   Orifice Properties
Name
Inlet Node
Outlet Node
Description
Tag
Type
Shape
Height
Width
Inlet Offset
Discharge Coeff.
Flap Gate
Time to Open /
Close
User-assigned orifice name.
Name of node on the inlet side of the orifice.
Name of node on the outlet side of the orifice.
Click the ellipsis button (or press Enter) to edit an optional
description of the orifice.
Optional label used to categorize or classify the orifice.
Type of orifice (SIDE or BOTTOM).
Orifice shape (CIRCULAR or RECT CLOSED).
Height of orifice opening when fully open (feet or meters).
Corresponds to the diameter of a circular orifice or the height of a
rectangular orifice.
Width of rectangular orifice when fully opened (feet or meters).
Depth or elevation of bottom of orifice above invert of inlet node
(feet or meters - see note below table of Conduit Properties).
Discharge coefficient (unitless). A typical value is 0.65.
YES if a flap gate exists which prevents backflow through the
orifice, or NO if no flap gate exists.
The time it takes to open a closed (or close an open) gated orifice
in decimal hours. Use 0 or leave blank if timed openings/closings
do not apply. Use Control Rules to adjust gate position.
                                      177

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B.10  Weir Properties
Name
Inlet Node
Outlet Node
Description
Tag
Type
Height
Length
Side Slope
Inlet Offset
Discharge Coeff.
Flap Gate
End Coeff.
End Contractions
User-assigned weir name.
Name of node on inlet side of weir.
Name of node on outlet side of weir.
Click the ellipsis button (or press Enter) to edit an optional
description of the weir.
Optional label used to categorize or classify the weir.
Weir type: TRANSVERSE, SIDEFLOW, V-NOTCH, or
TRAPEZOIDAL.
Vertical height of weir opening (feet or meters).
Horizontal length of weir opening (feet or meters).
Slope (width-to-height) of side walls for a V-NOTCH or
TRAPEZOIDAL weir.
Depth or elevation of bottom of weir opening from invert of inlet
node (feet or meters - see note below table of Conduit Properties).
Discharge coefficient for flow through the central portion of the
weir (for flow in CFS when using US units or CMS when using SI
units). Typical values are: 3.33 US (1.84 SI) for sharp crested
transverse weirs, 2.5 - 3.3 US (1.38 - 1.83 SI) for broad crested
rectangular weirs, 2.4 - 2.8 US (1.35 - 1.55 SI) for V-notch
(triangular) weirs
YES if the weir has a flap gate that prevents backflow, NO if it
does not.
Discharge coefficient for flow through the triangular ends of a
TRAPEZOIDAL weir. See the recommended values for V-notch
weirs listed above.
Number of end contractions for a TRANSVERSE or
TRAPEZOIDAL weir whose length is shorter than the channel it
is placed in. Values will be either 0, 1, or 2 depending on if no
ends, one end, or both ends are beveled in from the side walls.
                                      178

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B.11   Outlet Properties
Name
Inlet Node
Outlet Node
Description
Tag
Inlet Offset
Flap Gate
Rating Curve
FUNCTIONAL
- Coefficient
- Exponent
TABULAR
- Curve Name
User-assigned outlet name.
Name of node on inflow side of outlet.
Name of node on discharge side of outlet.
Click the ellipsis button (or press Enter) to edit an optional
description of the outlet.
Optional label used to categorize or classify the outlet.
Depth or elevation of outlet above inlet node invert (feet or meters
- see note below table of Conduit Properties).
YES if a flap gate exists which prevents backflow through the
outlet, or NO if no flap gate exists.
Method of defining flow (Q) as a function of depth or head (y)
across the outlet.
FUNCTIONAL/DEPTH uses a power function (Q = AyB) to
describe this relation where y is the depth of water above the
outlet's opening at the inlet node.
FUNCTIONAL/HEAD uses the same power function except that
y is the difference in head across the outlet's nodes.
TABULAR/DEPTH uses a tabulated curve of flow versus depth
of water above the outlet's opening at the inlet node.
TABULAR/HEAD uses a tabulated curve of flow versus
difference in head across the outlet's nodes.

Coefficient (A) for the functional relationship between depth or
head and flow rate.
Exponent (B) used for the functional relationship between depth
or head and flow rate.

Name of Rating Curve containing the relationship between depth
or head and flow rate (double-click to edit the curve).
                                        179

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B.12  Map Label Properties
Text
X-Coordinate
Y-Coordinate
Anchor Node
Font
Text of label.
Horizontal location of the upper-left corner of the label on the
Study Area Map.
Vertical location of the upper-left corner of the label on the Study
Area Map.
Name of node (or subcatchment) that anchors the label's position
when the map is zoomed in (i.e., the pixel distance between the
node and the label remains constant). Leave blank if anchoring is
not used.
Click the ellipsis button (or press Enter) to modify the font used to
draw the label.
                                     180

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APPENDIX C - SPECIALIZED PROPERTY EDITORS
C.1    Aquifer Editor

The Aquifer Editor is invoked whenever a new aquifer object is created or an existing aquifer
object is selected for editing. It contains the following data fields:

                                                Name
                                                User-assigned aquifer name.
Aquifer Editor
Property
Aquifer Name
Porosity
Wilting Point
F eld Capacity
Conductivity
Conduct. Slope
Tension Slope
Upper Evap. Fraction
Lower Evap. Depth
Lower GW Loss Rate
Bottom Elevation
Water Table Elevation
Unsat Zone Moisture
User-assigned aquifer name

OK [ Cancel

I
Value
A1
0.5
0.15
0.30
5.0
10.0
15.0
0.35
14.0
0.002
0.0
10.0
0.30


Help

3

\











'




                                               Porosity
                                               Volume of voids / total soil volume
                                               (volumetric fraction).

                                               Wilting Point
                                               Soil moisture content at which plants
                                               cannot survive (volumetric fraction).

                                               Field Capacity
                                               Soil moisture content after all free
                                               water has drained off (volumetric
                                               fraction).

                                               Conductivity
                                               Soil's saturated hydraulic conductivity
                                               (in/hr or mm/hr).

                                               Conductivity Slope
                                               Average slope of log(conductivity)
                                               versus soil moisture deficit (porosity
                                               minus moisture content)  curve
                                               (unitless).
Tension Slope
Average slope of soil tension versus soil moisture content curve (inches or mm).

Upper Evaporation Fraction
Fraction of total evaporation available for evapotranspiration in the upper unsaturated zone.

Lower Evaporation Depth
Maximum depth into the lower saturated zone over which evapotranspiration can occur (ft or m).

Lower Groundwater Loss Rate
Rate of percolation from saturated zone to deep groundwater (in/hr or mm/hr).
                                         181

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Bottom Elevation
Elevation of the bottom of the aquifer (ft or m).

Water Table Elevation
Elevation of the water table in the aquifer at the start of the simulation (ft or m).

Unsaturated Zone Moisture
Moisture  content of the  unsaturated upper zone of the aquifer at the  start of the simulation
(volumetric fraction) (cannot exceed soil porosity).
C.2     Climatology Editor

The  Climatology Editor is used to enter values for various climate-related variables required by
certain  SWMM simulations.  The  dialog is divided into five tabbed pages, where each page
provides a separate editor for a specific category of climate data.

Temperature Page
 Climatology Editor
   Temperature  Evaporation Wind Speed  Snow Melt  Areal Depletion
        Source of Temperature Data:


        0 No Data


        O Time Series
       O External Climate File
           D Start Reading File at
                           OK
Cancel
Help
                                            182

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The  Temperature  page of the  Climatology  Editor  dialog  is used  to  specify  the  source of
temperature data used for  snowmelt computations. It is also used to select a climate file as a
possible source for evaporation rates. There are three choices available:
No Data:
Time Series:
External
Climate File:
Select this choice if snowmelt is not being simulated and evaporation rates are
not based on data in a climate file.

Select this choice if the variation in temperature over the simulation period will
be described by one of the project's time series. Also enter (or select) the name of
the time series. Click the ^ button to make the Time Series Editor appear for the
selected time series.
Select this choice if min/max daily temperatures will be read from an external
climate  file. Also enter the name of the file (or click the  " button to search for
the file). If you want to start reading the climate file  at a particular date in time
that is  different than the  start date  of the  simulation  (as specified in the
Simulation Options), check off the "Start Reading  File  at" box and  enter a
starting date (month/day/year) in the date entry field next to it. Use this choice if
you want daily evaporation rates to be estimated from daily temperatures or be
read directly from the file.
                                            183

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Evaporation Page
 Climatology Editor
   Temperature  Evaporation  Wind Speed  Snow Melt Areal Depletion
        0 Constant Value
        O Time Series
                             0.0
   (in/day)
        O Directly From Climate File (see Temperature Page)

        O Computed from Temperatures in Climate File

        O Monthly Averages
        Monthly Evaporation (in/day)
Jan
Feb
Mar
Apr
May
Jun

Jul
Aug
Sep
Oct
Nov
Dec

        n Evaporate Only During Dry Periods
        Monthly Soil
        Recovery Pattern
                          OK
Cancel
The Evaporation page  of the Climatology Editor dialog is used to supply evaporation rates,  in
inches/day (or mm/day), for a study area. There are five choices for specifying these rates:

Constant:
Use this  choice if evaporation remains  constant over time. Enter the  value in the edit box
provided.

Time Series:
Select this choice if evaporation rates will be specified in a time series. Enter or select the name
                                                                ^>
of the time series in the dropdown combo box provided. Click the "S button to bring up the Time
Series editor for the selected series. Note  that for each date  specified in the time  series, the
evaporation rate remains constant at the  value supplied for that date  until the next date in the
series is reached (i.e., interpolation is not used on the series).
                                             184

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Directly From Climate File:
This choice indicates that daily evaporation rates will be read from the same climate file that was
specified for temperature. Enter values for monthly pan coefficients in the data grid provided.

Computed from Temperatures:
Hargreaves' method  will  be used  to  compute  daily evaporation rates  from the  daily  air
temperature record contained in the external climate file specified on the Temperature page of the
dialog. This method also uses the site's latitude, which can be entered on the Snowmelt page of
the dialog even if snow melt is not being simulated.

Monthly Averages:
Use this choice to supply  an average rate for each month of the year. Enter the value for each
month in the data grid provided. Note that rates remain constant within each month.

Evaporate Only During Dry Periods:
Select this option if evaporation can only occur during periods with no precipitation.

In addition this page allows the user to specify an optional Monthly Soil Recovery Pattern. This
is a time pattern whose factors adjust the rate at which infiltration capacity is  recovered during
periods with no precipitation. It applies to all subcatchments for any choice of infiltration method.
For example, if the normal infiltration recovery  rate was 1% during a specific time  period and a
pattern factor of 0.8 applied to this period, then the actual recovery rate would be 0.8%. The Soil
Recovery Pattern allows one to account for seasonal soil drying rates. In principle,  the variation
in pattern factors should mirror the variation in evaporation rates but might be influenced by other
factors such as seasonal groundwater levels. The ^ button is used to launch  the Time Pattern
Editor for the selected pattern.
                                           185

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Wind Speed Page
 Climatology Editor
   Temperature  Evaporation  Wind Speed  Snow Melt Areal I
     O From Climate File (see Temperature Page)

     0 Monthly Averages

      Monthly Wind Speed (mph)
Jan
Feb
Mar
Apr
May
Jun
0.0 0.0 0.0 0.0 0.0 0.0
Jul
Aug
Sep
Oct
Nov
Dec
0.0 0.0 0.0 0.0 0.0 0.0
              OK
    Cancel
Help
The Wind Speed page of the Climatology Editor dialog is used to provide average monthly wind
speeds.  These are used when computing  snowmelt rates under rainfall conditions.  Melt rates
increase  with increasing wind speed.  Units of wind  speed are  miles/hour  for US units and
km/hour for metric units. There are two choices for specifying wind speeds:
From Climate File:
Monthly Averages:
Wind speeds will be read from the same climate file that was specified
for temperature.

Wind speed is specified as an average value that remains constant in each
month of the year. Enter a  value for  each month in the data grid
provided. The default values are all zero.
                                           186

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Snowmelt Page
   Temperature  Evaporation  Wind Speed  Snow Melt  Areall <
           Dividing Temperature
           Between Snow and Rain
           (degrees F)

           AT I Weight (fraction)

           Negative Melt Ratio
           (fraction)

           Elevation above MSL
           (feet)

           Latitude (degrees)

           Longitude Correction
           (+/• minutes)
              OK
Cancel
Help
The Snowmelt page of the Climatology Editor dialog is used to supply values for the following
parameters related to snow melt calculations:

Dividing Temperature Between Snow and Rain
Enter the temperature below which precipitation falls as snow instead of rain. Use degrees F for
US units or degrees C for metric units.

ATI (Antecedent Temperature Index) Weight
This parameter reflects the  degree to which heat transfer within  a snow pack during non-melt
periods is affected by prior air temperatures. Smaller values reflect a thicker surface layer of snow
which results in reduced  rates  of heat transfer. Values must be between 0 and 1, and the default is
0.5.

Negative Melt Ratio
This is the  ratio of the heat transfer coefficient of a snow pack during non-melt conditions to the
coefficient during melt conditions. It must be a number between 0 and 1. The default value is 0.6.
                                            187

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Elevation Above MSL
Enter the average elevation above mean sea level for the study area, in feet or meters. This value
is used to provide a more accurate estimate of atmospheric pressure. The default is 0.0, which
results in a pressure of 29.9 inches Hg. The effect of wind on snow melt rates  during rainfall
periods is greater at higher pressures, which occur at lower elevations.

Latitude
Enter the latitude of the study area in degrees  North. This number is used when  computing the
hours of sunrise and sunset, which in turn are used to extend  min/max daily temperatures into
continuous values. It is also used to compute daily evaporation rates from daily temperatures. The
default is 50 degrees North.

Longitude Correction
This is a correction, in minutes of time, between true  solar time and  the standard clock time. It
depends on a location's longitude (6) and the  standard meridian of its time zone (SM) through the
expression  4(6-SM). This correction  is used to adjust the hours of sunrise and sunset when
extending daily min/max temperatures into continuous values. The default value is  0.
                                           188

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Areal Depletion Page
 Climatology Editor
   Evaporation  Wind Speed  Snow Melt  Areal Depletion
                    Fraction of Area Covered by Snow
Depth Ratio
0.0
0.1
0.2
0.3
0.4
0.5
0.6


Impervious
1.0
1.0
1.0
1.0
1.0
1.0
1.0
No Depletion
Natural Area
Pervious
1.0
1.0
1.0
1.0
1.0
1.0
1.0
No Depletion
Natural Area
A






V


              OK
Cancel
Help
The Areal Depletion page of the Climatology Editor Dialog is used to specify points on the Areal
Depletion Curves for both impervious and pervious surfaces within a project's study area.  These
curves define the relation between the area that remains snow covered and snow pack depth. Each
curve is defined by 10 equal increments of relative depth ratio between 0 and 0.9. (Relative depth
ratio is the ratio of an area's  current snow depth to the depth at which  there is 100% areal
coverage).

Enter values in the data grid provided for the fraction of each area that remains snow covered at
each specified relative depth ratio.  Valid numbers must be between  0  and  1, and be increasing
with increasing depth ratio.

Clicking the Natural Area button fills the grid  with  values that are typical of natural  areas.
Clicking the No Depletion button will fill the grid with all 1's, indicating that no areal depletion
occurs. This is the  default for new projects.
                                            189

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C.3    Control Rules Editor
    Control Rules Editor
 RULE PUMP1A
 IF NODE SU1 DEPTH >=  4
 THEM PUMP PUHP1 status
 PRIORITY 1
                  ON
 RULE PUMPIB
 IF NODE SU1 DEPTH < 1
 THEN PUMP PUHP1 status  =  OFF
 PRIORITY 1
                                     Cancel
                                           Help
 Click Help to review format of Control Rule statements
The Control Rules Editor is invoked whenever a new control rule is created or an existing rule is
selected for editing. The editor contains a memo field where the entire collection of control rules
is displayed and can be edited.

Control Rule Format

Each control rule is a series of statements of the form:

RULE  rulelD
IF
AND
OR
AND
Etc.
condition_l
condition_2
condition_3
condition 4
THEN   action_l
AND    action_2
Etc.

ELSE   action_3
AND    action_4
Etc.

PRIORITY value

where keywords are shown in boldface and rulelD is an ID  label  assigned to the rule,
condition_n is a Condition Clause, action_n is an Action Clause, and value is a priority
                                       190

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value  (e.g., a number from  1 to 5).  The formats used for Condition and Action clauses are
discussed below.

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

Blank lines between clauses are permitted and any text to the right of a semicolon is considered a
comment.

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  ...

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.


Condition Clauses

A Condition  Clause of a control rule has the following format:

object  id attribute  relation value

where:
object       =  a category of object
id            =  the object's ID label
attribute  =  an attribute or property of the obj ect
relation    =  a relational operator (=, o, <, <=, >, >=)
value       =  an attribute value

Some examples of condition clauses are:

NODE   N23  DEPTH   >   10
PUMP   P45  STATUS =   OFF
SIMULATION CLOCKTIME =  22:45:00
                                         191

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The objects and attributes that can appear in a condition clause are as follows:
Object
NODE
LINK
PUMP
ORIFICE
WEIR
SIMULATION
Attributes
DEPTH
HEAD
INFLOW
FLOW
DEPTH
STATUS
FLOW
SETTING
TIME
DATE
CLOCKTIME
Value
numerical value
numerical value
numerical value
numerical value
numerical value
ON or OFF
numerical value
fraction open
elapsed time in decimal hours or hr:min:sec
month/day/year
time of day in hr:min:sec
Action Clauses

An Action Clause of a control rule can have one of the following formats:

PUMP  id  STATUS  = ON/OFF
PUMP/ORIFICE/WEIR/OUTLET  id  SETTING =  value

where the meaning of SETTING depends on the object being controlled:

    •   for Pumps it is a multiplier applied to the flow computed from the pump curve,
    •   for Orifices it is the fractional amount that the orifice is fully open,
    •   for Weirs it is the fractional amount of the original freeboard that exists (i.e., weir control
       is accomplished by moving the crest height up or down),
    •   for Outlets it is a multiplier applied to the flow computed from the outlet's rating curve.

Some examples of action clauses are:
PUMP  P67  STATUS  =  OFF
ORIFICE  0212 SETTING =  0.5


Modulated Controls

Modulated controls are control rules that provide for a continuous degree of control applied to a
pump or flow regulator as determined by the value of some controller variable,  such as water
depth at a node, or by time. The functional relation between the control setting and the  controller
                                          192

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variable can be specified by using a Control Curve, a Time  Series,  or a PID Controller.  Some
examples of modulated control rules are:

RULE  MCI
IF NODE  N2  DEPTH >= 0
THEN  WEIR  W25 SETTING  =  CURVE C25

RULE  MC2
IF SIMULATION TIME  >  0
THEN  PUMP  P12 SETTING  =  TIMESERIES  TS101

RULE  MC3
IF LINK  L33  FLOW <> 1.6
THEN  ORIFICE  O12 SETTING =  PID  0.1  0.0  0.0

Note how a modified form of the action clause is used to specify the name of the control curve,
time series or PID parameter set that defines the degree of control. A PID parameter set contains
three values - a proportional gain coefficient, an integral  time (in minutes), and a derivative time
(in minutes). Also,  by convention  the  controller  variable used in  a  Control Curve  or PID
Controller will  always be the object and  attribute  named  in the last condition clause of the rule.
As an example, in rule MC 1 above Curve C25 would define how the fractional setting  at Weir
W25 varied with the water depth at Node  N2. In rule MC3, the PID controller adjusts the opening
of Orifice O12 to maintain a flow of 1.6 in Link L33.


PID Controllers

A PID (Proportional-Integral-Derivative)  Controller is a generic closed-loop control scheme that
tries to maintain  a desired set-point on  some process variable by  computing and applying  a
corrective action that adjusts the process accordingly. In the  context of a  hydraulic conveyance
system a PID controller might be used to adjust the opening on a gated orifice to maintain a target
flow rate in a specific conduit or to adjust a variable speed pump to maintain a desired depth in a
storage unit. The classical PID controller has the form:
    m(t) = K
where m(t) = controller output, Kp = proportional coefficient (gain), Tt = integral time, Td =
derivative time,  eft) = error (difference between setpoint and  observed variable value), and t =
time.  The performance of a PID controller is determined by the  values assigned to the coefficients
Kp, T,, and Td.

The controller output  mft) has the same meaning as a link setting used in a rule's Action Clause
while dt is the current flow routing time step in minutes. Because link settings are relative values
(with respect to either a pump's standard operating curve or to the full opening height of an orifice
or weir) the error eft) used by the controller is also a relative value. It is defined as the difference
between the control variable setpoint  x* and its value  at time  t, xft), normalized to the setpoint
value: eft) = (x*-x(t)) /x*.
                                           193

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Note that for direct action control, where an increase in the link setting causes an increase in the
controlled variable,  the  sign  of Kp  must be positive. For reverse  action control, where the
controlled variable decreases as the link setting increases, the sign of Kp must be negative. The
user must recognize whether the control is direct or reverse action and use the proper sign on Kd
accordingly. For example, adjusting an orifice opening to maintain a desired downstream flow is
direct action. Adjusting it to maintain an upstream water level is reverse action. Controlling a
pump to maintain a fixed wet well water level would be reverse action while using it to maintain
a fixed downstream flow is direct action.
C.4     Cross-Section Editor
          o
        Standard circular pipe.
                                 Max. Depth
                                             Help
The Cross-Section Editor dialog is used to specify the shape and dimensions of a conduit's cross-
section. When a shape is selected from the dropdown combo box an appropriate set of edit fields
appears for describing the dimensions of that shape. Length dimensions are in units of feet for US
units and meters for SI units. Slope values represent ratios of horizontal to vertical distance. The
Barrels field specifies how many identical parallel conduits exist between its end nodes.

If an Irregular shaped section is chosen, a drop-down edit box will appear where you can enter or
select the name of a Transect object that describes the cross-section's geometry. Clicking the Edit
button next to the edit box will bring up the Transect Editor from which you can edit the transect
data.
                                            194

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C.5    Curve Editor
 Pump Curve Editor
   Curve Name
   PUMP_CURVE1
Pump Type
 TYPE 4
   Description

1
2
3
4
5
6
7
8
9
Depth
(ft)
0
4
4.75






Flow
(CFS)
0.45
0.45
0.9






A








V
The Curve Editor dialog is invoked whenever a new curve object is created or an existing curve
object  is selected for editing. The editor adapts  itself to  the  category of curve being edited
(Storage, Tidal, Diversion, Pump, or Rating). To use the Curve Editor:

    •   Enter values for the following data entry fields:

       Name             Name of the curve.
       Type             (Pump Curves Only). Choice of pump curve type as described in
                         Section 3.2

       Description       Optional comment or description of what the curve represents. Click
                         the & button to launch a multi-line comment editor if more than one
                         line is needed.
       Data Grid        The curve's X,Y data.
    •   Click the View button to see a graphical plot of the curve drawn in a separate window.
    •   If additional rows are needed in the Data Grid, simply press the Enter key when in the
       last row.
    •   Right-clicking over the Data Grid will make a popup Edit menu appear. It contains
       commands to cut, copy, insert, and paste selected cells in the grid as well as options to
       insert or delete  a row.
                                           195

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You can also click the Load button to load in a curve that was previously saved to file or click the
Save button to save the current curve's data to a file.
C.6    Groundwater Flow Editor
 Groundwater Flow Editor
Property
Aquifer Name
Receiving Node
Value


Surface Elevation
Groundwater Flow Coeff.
Groundwater Flow Expon.
Surface Water Flow Coeff.
Surf ace Water Flow Expon.
Surface-GW Interaction Coeff.
Fixed Surface Water Depth
X
0
0
0
0
0
0
0
Threshold Groundwater Elev.
Name of aquifer object that lies below subcatchment
(leave blank for no groundwater).
OK
Cancel
Help

The  Groundwater  Flow  Editor dialog is  invoked  when  the Groundwater property of  a
subcatchment is being edited. It is used to link a subcatchment to both an aquifer and to a node of
the drainage system that exchanges groundwater with the  aquifer. It also specifies coefficients
that determine the rate of groundwater flow between the aquifer and the node. These coefficients
(Al, A2, Bl, B2, and A3) appear in the following equation that computes groundwater flow as a
function of groundwater and surface water levels:
                                  + A3HC
    Q    = Al(k    -H*Jl -A2(HSW -
where:
    Qgw
    TT
    ngw
    Hsw
    H*
=  groundwater flow (cfs per acre or cms per hectare)
=  height of saturated zone above bottom of aquifer (ft or m)
=  height of surface water at receiving node above aquifer bottom (ft or m)
=  threshold groundwater height (ft or m).
                                          196

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 ?2&&&&<&(&
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       If groundwater flow is simply proportional to the difference in groundwater and surface
       water heads, then set the Groundwater and Surface Water Flow Exponents (Bl and B2)
       to 1.0, set the Groundwater Flow Coefficient (Al) to the proportionality factor, set the
       Surface Water Flow Coefficient (A2) to the same  value as Al, and set the Interaction
       Coefficient (A3) to zero.

       Note that when conditions warrant, the groundwater flux can be negative, simulating flow
       into the aquifer from the channel, in the manner of bank storage. An exception occurs
       when A3  ^ 0, since the surface water - groundwater interaction term is usually derived
       from groundwater flow models that assume unidirectional flow. Otherwise, to ensure that
       negative fluxes will not occur, one can make Al greater than or equal to A2, Bl greater
       than or equal to B2, and A3 equal to zero.
C.7     Infiltration Editor
 Max. Infil. Rate
 Mir Infil. Rate
 Decay Constant
 Drying Time
 Max. Volume
   3.0
   0.5
   4
 Maximum rate on the Morton infiltration curve (in/hr or
 mm/hr)
      OK
Cancel
Help
The Infiltration Editor dialog is used to specify values for the parameters that describe the rate at
which rainfall infiltrates into the upper soil zone in a subcatchment's pervious area. It is invoked
when editing the Infiltration property of a subcatchment. The infiltration parameters depend on
which infiltration model was selected for the project: Horton, Green-Ampt, or Curve Number.
The choice of infiltration model can be made either by editing the project's Simulation Options
(see Section 8.1) or by changing the project's Default Properties (see Section 5.4).
                                           198

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Morton Infiltration Parameters

The following data fields appear in the Infiltration Editor for Horton infiltration:

Max. Mil. Rate
Maximum infiltration rate on the Horton curve (in/hr or mm/hr). Representative values are as
follows:
    1.  DRY soils (with little or no vegetation):

       •   Sandy soils: 5 in/hr
       •   Loam soils: 3 in/hr

       •   Clay soils: 1 in/hr
    2.  DRY soils (with dense vegetation):
       •   Multiply values in A. by 2
    3.  MOIST soils:

       •   Soils which have drained but not dried out (i.e., field capacity):
           Divide values from A and B by 3.
       •   Soils close to  saturation:
           Choose value close to min. infiltration rate.
       •   Soils which have partially dried out:
           Divide values from A and B by 1.5 - 2.5.

Min. Infil. Rate
Minimum infiltration rate on the Horton curve (in/hr or mm/hr). Equivalent to the soil's saturated
hydraulic  conductivity. See the Soil Characteristics Table in Section A.2 for typical values.

Decay Const.
Infiltration rate decay constant for the Horton curve (I/hours).  Typical values range between 2
and 7.

Drying Time
Time in days for a fully saturated soil to dry completely. Typical values range from 2 to 14 days.

Max. Infil. Vol.
Maximum infiltration volume possible (inches or mm, 0 if not applicable). It can be estimated as
the difference between  a  soil's porosity  and its wilting point times the depth of the infiltration
zone.


Green-Ampt Infiltration Parameters

The following data fields appear in the Infiltration Editor for Green-Ampt infiltration:

Suction Head
Average value of soil capillary suction along the wetting front (inches or mm).
                                            199

-------
Conductivity
Soil saturated hydraulic conductivity (in/hr or mm/hr).

Initial Deficit
Fraction  of soil volume  that is  initially dry  (i.e., difference between soil porosity  and initial
moisture content). For a  completely drained soil,  it is the difference between the soil's porosity
and its field capacity.

Typical values for all of these  parameters can be found in the Soil Characteristics Table in
Section A.2.


Curve Number Infiltration Parameters

The following data fields appear in the Infiltration Editor for Curve Number infiltration:

Curve Number
This is the SCS curve number which is tabulated in the publication SCS Urban Hydrology for
Small Watersheds, 2nd Ed., (TR-55), June 1986. Consult the Curve Number Table (Section A.4)
for a listing of values by soil group, and the accompanying Soil Group Table (Section A. 3) for the
definitions  of the various groups.

Conductivity
This property has been deprecated and is no longer used.

Drying Time
The number of days it takes a fully saturated soil to dry. Typical values range between 2 and 14
days.
                                           200

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C.8    Inflows Editor

The Inflows Editor dialog is used to assign Direct, Dry Weather, and RDII inflow into a node of
the drainage system. It is invoked whenever the Inflows property of a Node object is selected in
the Property Editor. The dialog consists of three tabbed pages that provide  a special editor for
each type of inflow.

Direct Inflows Page
 Inflows for Node 82309
   Direct  Dry Weather RDII
     Constituent

     Baseline

     Baseline Pattern

     Time Series

     Scale Factor
                     FLOW
82309.1 nf low
V
1.0
          Inflow = (Baseline Value) x (Baseline Pattern)*
                  (Time Series Value) x (Scale Factor)

        If Baseline or Time Series is left blank its value is 0. If
           Baseline Pattern is left blank its value is 1.0.
             OK
   Cancel
Help
The Direct page on the Inflows Editor dialog is used to specify the time history of direct external
flow and water quality entering a node of the drainage system. These inflows are represented by
both a constant and time varying component as follows:

Inflow  at  time  t =  (baseline value) * (baseline  pattern factor)  +
                           (scale  factor) * (time  series  value at time  t)

The dialog consists of the following input fields:
                                           201

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Constituent
Selects the constituent (FLOW or one of the project's specified pollutants) whose direct inflow will
be described.

Baseline
Specifies the value of the constant baseline component of the constituent's inflow. For FLOW, the
units are the project's flow units. For pollutants, the units are the pollutant's concentration units if
inflow is  a  concentration,  or can  be any mass flow units if the inflow is  a  mass flow  (see
Conversion Factor below). If left blank then no baseline inflow is assumed.

Baseline Pattern
An optional Time Pattern whose factors adjust the baseline inflow on either an hourly, daily, or
monthly basis (depending on the type of time pattern specified). Clicking the & button will bring
up the Time Pattern Editor dialog for the selected time pattern. If left blank, then no adjustment is
made to the baseline inflow.

Time Series
Specifies the name of the time series that contains inflow data for the selected constituent. If left
blank then no direct inflow will occur for the selected constituent at the node in question. You can
         &,
click the *S button to bring up the Time Series Editor dialog for the selected time series.

Scale Factor
A multiplier used to adjust the values of the constituent's inflow time series. The baseline value is
not adjusted by this factor.  The scale factor can have several uses, such as allowing one to easily
change the magnitude of an inflow hydrograph while keeping its shape the same, without having
to re-edit the entries in the hydrograph's time series.  Or it can allow a group of nodes sharing the
same time series to have their inflows behave in a time-synchronized fashion while letting their
individual magnitudes be different.  If left blank the scale factor defaults to  1.0.

Inflow Type
For pollutants,  selects  the  type of inflow data contained in the time  series as being either a
concentration (mass/volume) or mass flow rate (mass/time). This field does not appear for FLOW
inflow.

Conversion Factor
A numerical factor used to convert the units  of pollutant mass flow rate  in the  time  series  data
into concentration mass units  per second.  For  example, if the time series data were in pounds per
day and the pollutant concentration defined in the project was mg/L, then the conversion factor
value would be  (453,590 mg/lb) / (86400 sec/day) = 5.25 (mg/sec) per (Ib/day).

More than one  constituent  can be  edited while the dialog is active by simply selecting another
choice for the Constituent property. However, if the Cancel button  is clicked then any changes
made to all constituents will be ignored.

 ''T"1
 W     If a pollutant is assigned a direct inflow in terms of concentration, then one must  also
        assign a direct  inflow to flow, otherwise no pollutant inflow will  occur.  An exception is
        at submerged outfalls where pollutant intrusion can occur during periods of reverse flow.
        If pollutant inflow is defined in terms of mass, then  a flow inflow  time series is not
        required.
                                           202

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Dry Weather Inflows Page
   Direct   Dry Weather  RDII
     Constituent

     Average Value
     (CFS)

     Time Patterns
FLOW
v
1.2
Monthly!
                      Hourly!
     NOTE: Leave Average Value field blank to remove any dry
     weather inflow for a given constituent at this node.
The Dry Weather page of the Inflows Editor dialog is used to specify a continuous source of dry
weather flow entering a node of the drainage system. The dialog consists of the following input
fields:

Constituent
Selects the constituent (FLOW  or one of the project's  specified pollutants) whose dry weather
inflow will be specified.

Average Value
Specifies the  average (or baseline) value of the  dry  weather inflow of the constituent in the
relevant units (flow units for flow, concentration units for pollutants). Leave blank if there is no
dry weather flow for the selected constituent.

Time Patterns
Specifies the names of the time patterns  to be used to allow the dry weather flow to  vary in a
periodic fashion by month of the year, by day of the week, and by time of day (for both weekdays
and weekends). One  can either type in a name or select a previously defined pattern from the
dropdown list of each combo box. Up to four different types of patterns can be assigned. You can
click the & button next to each Time Pattern field to edit the respective pattern.
                                            203

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More than one constituent can be edited while the dialog is active by simply selecting another
choice for the Constituent property. However, if the Cancel button is clicked then any changes
made to all constituents will be ignored.
RDM Inflow Page
   Direct   Dry Weather, RDM
Sewershed Area,
(acres)
                                20
     NOTE: Leave Unit Hydrograph Group field blank to remove
     any RDII inflow at this node.
The  RDII  page  of the  Inflows Editor dialog is used  to specify  RDII (rainfall-dependent
infiltration/inflow) for the node in question.  The editor contains the following two input fields:

Unit Hydrograph Group
Enter (or select from the dropdown list) the name of the Unit Hydrograph group that applies to
the node in question. The unit hydrographs in the group are used in combination with the group's
assigned rain gage to develop a time series of RDII inflows per unit area over the period of the
simulation. Leave this field blank to indicate that the node  receives no RDII inflow. Clicking the
 >
"-1 button will launch the Unit Hydrograph Editor for the UH group specified.

Sewershed Area
Enter the  area (in  acres or hectares)  of the  sewershed that contributes  RDII to the node in
question. Note this area will typically be only a small, localized portion of the subcatchment area
that contributes surface runoff to the node.
                                           204

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C.9     Initial Buildup Editor
Subcatchment 1 [xj
Property
N-Perv
Dstore-lmperv
Dstore-Petv
%Zero-lmperv
Subarea Routing
Percent Routed
Infiltration
Groundwater
Snow Pack
Land Uses
Initial Buildup
Curb Length

Value
0.10
0.05
0.05
25
OUTLET
100
MORTON
NO

1
NONE
K^ 	


*
i
1
v
Initial pollutant buildup on subcatchment
(click to edit)
                                               Initial Buildup Editor
                                               Pollutant
   Initial Buildup (Ibs/ac)
                                               TSS
                                               Lead
   10
                                               Enter initial buildup of pollutants on subcatchment 1
                                                     OK
Cancel
Help
The Initial Buildup Editor is invoked from the Property Editor when editing the Initial Buildup
property of a subcatchment.  It specifies the  amount of pollutant buildup existing  over the
subcatchment  at the start of the simulation.  The editor consists  of a data entry grid  with two
columns. The  first column lists the name of each pollutant in the project and the second column
contains edit boxes for entering the initial buildup values. If no buildup value is supplied for a
pollutant,  it is assumed to be 0. The units for buildup are  either pounds per acre when US units
are in use  or kilograms per hectare when SI metric units are in use.

If a non-zero value is specified for the  initial buildup of a pollutant, it will override any initial
buildup computed from the  Antecedent Dry Days parameter specified  on the Dates page of the
Simulation Options dialog.
C.10   Land Use Editor

The  Land Use Editor dialog is used to define a category of land use for the study area and to
define its pollutant buildup and washoff characteristics. The dialog contains three tabbed pages of
land use properties:
    •   General Page (provides land use name and street sweeping parameters)
    •   Buildup Page (defines rate at which pollutant buildup occurs)
    •   Washoff Page (defines rate at which pollutant washoff occurs)
                                           205

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General Page
   General  Buildup  Washoff
   Land Use Name
   Description
   STREET SWEEPING
    Interval
    Availability
    Last Swept
   Residential
   User assigned name of land use.
        OK
Cancel
The General page of the Land Use Editor dialog describes the following properties of a particular
land use category:

Land Use Name
The name assigned to the land use.

Description
An optional comment or description of the land use (click the ellipsis button or press Enter to
edit).

Street Sweeping Interval
Days between street sweeping within the land use.
Street Sweeping Availability
Fraction of the buildup of all pollutants that is available for removal by sweeping.

Last Swept
Number of days since last swept at the start of the simulation.

If street sweeping does not apply to the land use, then the last three properties can be left blank.
                                            206

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Buildup Page
Land Use Editor V]


General

Buildup

Washoff|
Pollutant


Property
Function




TSS v
Value

Max. Buildup
Rate Constant

Power /Sat. Constant
Normalize!

SAT



V
50
0
2
AREA

Buildup function: POW = power, EXP = exponential,
SAT = saturation, EXT = external time series.


f OK 	 "1



Cancel



Help


The Buildup page of the Land Use Editor dialog describes the properties associated with pollutant
buildup over the land during dry weather periods. These consist of:

Pollutant
Select the pollutant whose buildup properties are being edited.

Function
The type of buildup function to use for the pollutant. The choices are NONE  for no buildup, POW
for power function buildup, EXP for exponential function buildup SAT for saturation  function
buildup, and EXT for buildup supplied by an external time series. See the discussion of Pollutant
Buildup in  Section 3.3.9 for explanations of these different functions. Select NONE if no buildup
occurs.

Max.  Buildup
The maximum  buildup that can  occur, expressed as  Ibs (or kg) of the pollutant per unit of the
normalizer  variable (see below). This is  the  same as the  Cl  coefficient used in the buildup
formulas discussed in Section 3.3.9.
                                           207

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The following two properties apply to the POW, EXP, and SAT buildup functions:

Rate Constant
The time constant that governs the rate of pollutant buildup.  This is the  C2 coefficient in the
Power and Exponential buildup formulas discussed in Section 3.3.9. For Power buildup its units
are mass / days raised to a power, while for Exponential buildup its units are I/days.

Power/Sat. Constant
The exponent C3 used in the Power buildup formula, or the half-saturation constant C2 used in
the Saturation buildup formula discussed in Section 3.3.9. For the latter case, its units are days.

The following two properties apply to the EXT (External Time Series) option:

Scaling Factor
A multiplier used to adjust the buildup rates listed in the time series.

Time Series
The name of the  Time Series that contains buildup rates (as mass per normalizer per day).

Normalizer
The variable to which buildup is normalized on a per unit basis. The choices are either land area
(in acres or hectares) or curb length. Any units of measure can be used for curb length, as long as
they remain the same for  all subcatchments in the project.

When there are  multiple pollutants,  the user must select each pollutant  separately  from the
Pollutant dropdown list and specify its pertinent buildup properties.
                                           208

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Washoff Page
 Land Use Editor
   General  Buildup  Washoff
   Pollutant
   TSS
   Property
   Value
   Function
   Coefficient
   Exponent
   Cleaning Effic.
   BMP Effic.
   EXP
   0.1
  Washoff function: EXP = exponential, RC = rating curve,
  EMC = event mean concentration.
        OK
Cancel
Help
The  Washoff page of  the  Land Use Editor dialog describes the properties associated with
pollutant washoff over the land use during wet weather events. These consist of:

Pollutant
The name of the pollutant whose washoff properties are being edited.

Function
The choice of washoff function to use for the pollutant. The choices are:
    •  NONE  no washoff

    •  EXP   exponential washoff

    •  RC     rating curve washoff

    •  EMC   event-mean concentration washoff.

The formula for each of these functions is discussed in Section 3.3.9 under the Pollutant Washoff
topic.

Coefficient
This is the value of Cl in  the  exponential  and rating curve formulas,  or the event-mean
concentration.

Exponent
The exponent used in the exponential and rating curve washoff formulas.
                                            209

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Cleaning Efficiency
The street cleaning removal efficiency (percent) for the pollutant. It represents the fraction of the
amount that is available for removal on the land use as a whole (set on the General page of the
editor) which is actually removed.

BMP Efficiency
Removal efficiency (percent) associated with any Best Management Practice that might have
been implemented.  The washoff load computed at each time step is simply reduced by this
amount.

As with the Buildup page, each pollutant must be selected in turn from the Pollutant dropdown
list and have its pertinent washoff properties defined.
C.11   Land Use Assignment Editor
 Residential
 Undeveloped
      OK
Cancel
Help
The Land Use Assignment editor is invoked from the Property Editor when editing the Land Uses
property  of a subcatchment. Its purpose is  to assign land uses to the subcatchment for water
quality simulations. The percent of land area in the subcatchment covered by each land use is
entered next to its respective land use category. If the land use is not present its field can be left
blank. The percentages entered do not necessarily have to add up to 100.
                                          210

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C.12   LID Control Editor
 LID Control Editor
   Control Name:

   LID Type:

   Process Layers:
                       BiocelH
Bio-Retention Cell
                        -
     Surface  Soil    Storage  Underdrain
       Thickness
       (in. or mm)

       Porosity
       (volume fraction)

       Field Capacity
       (volume fraction)

       Wilting Point
       (volume fraction)

       Conductivity
       (in/hr or mm/hr)

       Conductivity Slope

       Suction Head
       (in. or mm)
           OK
 Cancel
The LID Control Editor is used to define a low impact development control that can be deployed
throughout a study area to store, infiltrate, and evaporate subcatchment runoff. The design of the
control is made on a per-unit-area basis so that it can be placed in any number of subcatchments
at different sizes or number of replicates. The editor contains the following data entry fields:

Control Name
A name used to identify the particular LID control.

LID Type
The generic type of LID being defined (bio-retention cell, porous pavement, infiltration trench,
rain barrel, or vegetative swale).
                                             211

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Process Layers
These are a tabbed set of pages containing data entry fields for the vertical layers and underdrain
that comprise an LID control. They include some combination of the following, depending on the
type of LID selected: Surface Layer, Pavement Layer, Soil Layer, Storage Layer, and Underdrain
System.

The  Surface Layer page of the LID Control Editor is used to describe the surface properties of
bio-retention  cells, porous  pavement,  infiltration   trenches,  and  vegetative  swales.  These
properties are:

Storage Depth
When confining walls or berms are present this is the maximum depth to which water can pond
above the surface of the unit before overflow occurs (in inches or mm). For LIDs that experience
overland flow it is the height of any surface depression storage. For swales, it is the height of its
trapezoidal cross section.

Vegetative Cover Fraction
The fraction of the storage area above the surface that is filled with vegetation.

Surface Roughness
Manning's n for overland flow over the surface of porous pavement or a vegetative swale. Use 0
for other types of LIDs.

Surface Slope
Slope of porous pavement surface or vegetative swale (percent). Use 0 for other types of LIDs.

Swale Side Slope
Slope (run over rise) of the  side walls of a vegetative swale's cross section. This value is ignored
for other types of LIDs.

 ''"!)
 V    If either Surface Roughness or Surface Slope values are 0 then any ponded water that
       exceeds the storage depth is assumed to completely overflow the LID control within a
       single time step.


The Pavement Layer page  of the LID  Control Editor supplies values for the following properties
of a porous pavement LID:

Thickness
The thickness of the pavement layer (inches or mm). Typical values are 4 to 6 inches (100 to 150
mm).

Void Ratio
The volume of void space relative to the volume of solids in the pavement for continuous systems
or for the fill material used in modular systems. Typical values for pavements are 0.12 to 0.21.
Note that porosity = void ratio / (1 + void ratio).

Impervious Surface Fraction
Ratio of impervious paver  material  to total area for modular  systems; 0 for continuous porous
pavement systems.
                                           212

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Permeability
Permeability of the concrete or asphalt used in continuous systems or hydraulic conductivity of
the fill material (gravel or sand) used in modular systems (in/hr or mm/hr). The permeability of
new porous concrete or asphalt is very high (e.g., hundreds of in/hr) but can drop off over time
due to clogging by fine particulates in the runoff (see below).

Clogging Factor
Number of pavement layer void  volumes  of runoff treated it takes to  completely clog the
pavement. Use a value of 0 to  ignore clogging. Clogging progressively reduces the pavement's
permeability in direct proportion to the cumulative volume of runoff treated.

If one has an estimate of the number of years  it takes to fully  clog the system (Yclog), the
Clogging Factor can be computed as: Yclog * Pa * CR * (1 + VR) * (1 - ISF) / (T * VR) where
Pa is the  annual  rainfall amount over the site,  CR is the pavement's capture  ratio (area that
contributes runoff to the  pavement divided by area of the pavement itself), VR is the system's
Void Ratio, ISF is the Impervious Surface Fraction, and T is the pavement layer Thickness.

As an example, suppose it takes 5 years to clog a continuous porous pavement system that serves
an area where the annual rainfall is 36 inches/year. If the pavement is  6 inches thick, has a void
ratio of 0.2 and captures runoff only from its own surface, then the  Clogging Factor is 5 x 36 x (1
+ 0.2)76/0.2= 180.

The  Soil Layer page of the LID Control Editor describes the properties of the engineered soil
mixture used in bio-retention types  of LIDs. These properties are:

Thickness
The thickness of the soil layer (inches or mm). Typical values range from 18 to 36 inches (450 to
900 mm) for rain gardens, street planters and other types of land-based bio-retention units, but
only 3 to 6 inches (75 to 150 mm) for green roofs.

Porosity
The volume of pore space relative to total volume of soil (as a fraction).

Field Capacity
Volume of pore water relative to total volume after the soil has been allowed to drain fully (as a
fraction). Below this level, vertical drainage of water through the  soil layer does not occur.

Wilting Point
Volume of pore water relative to  total volume for a well dried  soil where  only bound  water
remains (as a fraction). The moisture content of the soil cannot fall below this limit.

Conductivity
Hydraulic conductivity for the fully saturated soil (in/hr or mm/hr).

Conductivity Slope
Slope of the  curve of log(conductivity) versus soil moisture content (dimensionless).  Typical
values range from 5 for sands to 15 for silty clay.

Suction Head
The  average value of soil capillary suction along the wetting front (inches or mm). This  is the
same parameter as used in the Green-Ampt infiltration model.
                                           213

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 V    Porosity, field capacity, conductivity and conductivity slope are the same soil properties
       used for Aquifer objects when modeling groundwater, while suction head is the same
       parameter used  for Green-Ampt  infiltration. Except here they apply to the special soil
       mixt used in a LID unit rather than the site's naturally occuring soil.

The Storage Layer page of the LID Control Editor  describes the properties of the crushed stone
or gravel layer used in bio-retention cells, porous pavement systems, and infiltration trenches as a
bottom storage/drainage layer. It is also used to specify the height of a rain barrel (or cistern). The
following data fields are displayed:

Height
This is the height of a rain barrel or thickness of a gravel layer (inches or mm). Crushed stone and
gravel layers are typically 6 to 18  inches (150 to  450 mm) thick while single family home rain
barrels range in height from 24 to 36 inches (600 to 900 mm).

The following data fields do not apply to Rain Barrels.

Void Ratio
The volume of void space relative to the volume of solids in the layer. Typical values range from
0.5 to 0.75 for gravel beds. Note that porosity = void ratio / (1 + void ratio).

Filtration Rate
The maximum rate at which water  can flow out the bottom of the layer after it is first constructed
(in/hr or mm/hr). Typical values for gravels are 10  to 30 in/hr (250 to 750 mm/hr). If the layer
contains a sand bed beneath  it then the conductivity of the  sand should  be used. If there is  an
impermeable floor or liner below  the layer then  use a value of 0. The  actual exfiltration rate
through the bottom will be the smaller of this limiting rate and the normal infiltration rate into the
soil below the layer.

Clogging Factor
Total  volume of treated  runoff it takes to completely clog the bottom of the layer divided by the
void volume of the layer. Use a value of 0 to ignore clogging. Clogging progressively reduces the
Filtration Rate in direct proportion  to the cumulative volume of runoff treated and may only be of
concern for infiltration trenches with permeable bottoms and no under drains.

LID storage layers can contain an optional underdrain system that collects stored water from the
bottom of the layer and conveys it to a conventional storm drain. The Underdrain page of the
LID Control Editor describes the properties of this  system. It contains the following data entry
fileds:

Drain Coefficient and Drain Exponent
Coefficient  C and  exponent n that determines the rate of flow through the underdrain as a
function of height of stored  water above the drain height.  The following equation is  used to
compute this flow rate (per unit area of the LID unit):

    q = C(h-Hd)n

where q is outflow (in/hr or mm/hr), h height of stored water (inches or mm), and Hd is the drain
height. If the layer does not have an underdrain then  set C to 0. A typical value for n would be 0.5
                                           214

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(making the drain act like an orifice). A rough estimate for C can be based on the time T required
to drain a depth D of stored water. For n = 0.5, C = 2D1/2/T.

Drain Offset Height
Height Hd of any underdrain piping above the bottom of a storage layer or rain barrel (inches or
mm).

Drain Delay (for Rain Barrels only)
The number of dry weather hours that must elapse before the drain line in a rain barrel is opened
(the line is assumed to be closed once rainfall begins). This parameter is ignored for other types
ofLIDs.
C.13   LID Group Editor
 LID Controls for Subcatchment S1
    Control Name
LID Type
% Of Area
% From Imperv
Report File
    BiocelM
BC
    RainB artels
FIB
5.739
20
0.138
20
                                                                               Edit
                                                                              Delete
The LID Group Editor is invoked when the LID Controls property of a Subcatchment is selected
for editing. It is used to identify a group of previously defined LID controls that will be placed
within the Subcatchment, the sizing of each control, and what percent of runoff from the non-LID
portion of the Subcatchment each should treat.

The editor displays the current group of LIDs placed in the Subcatchment along with buttons for
adding an LID unit, editing a selected unit, and deleting a selected unit. These actions can also be
chosen by hitting the Insert key, the Enter key, and the Delete key, respectively. Selecting Add
or Edit will bring up an LID Usage Editor where one can enter values for the data fields shown in
the Group Editor.

Note that the total % Of Area for all of the the LID units within a Subcatchment must not exceed
100%. The same applies  to % From Impervious. Refer to the LID Usage Editor  for the meaning
of these parameters.
                                           215

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C.14   LID Usage Editor
 LID Usage Editor
   Control Name
                    RainB artels
   Number of Replicate Units

   H3 LID Occupies Full Subcatchment

   Area of Each Unit (sq ft or sq m)

   % of Subcatchment Occupied

   Top Width of Overland Flow
   Surface of Each Unit (ft or m)
   % Initially Saturated
   % of Impervious Area Treated
   O Send Outflow to Pervious Area
   Detailed Report File (Optional)
                      Cancel
Help
The LID Usage Editor is invoked from a subcatchment's LID Group  Editor to specify how a
particular LID control will be deployed within the Subcatchment.  It contains the following data
entry fields:

Control Name
The name of a previously defined LID control to be used in the Subcatchment. (LID controls are
added to a project by using the Data Browser.)

Number of Replicate Units
The number of equal size units of the LID practice  (e.g., the number of rain barrels) deployed
within the Subcatchment.
                                            216

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Area of Each Unit
The surface area devoted to each replicate LID unit (sq. ft or sq. m). If the LID Occupies Full
Subcatchment box  is checked,  then  this field becomes disabled and  will  display the total
subcatchment area divided by the number of replicate units. (See Section 3.3.14 for options on
placing LIDs within  subcatchments.) The label below this field indicates  how much of the total
subcatchment area is devoted to the particular LID being deployed.

Top Width of Overland Flow Surface
The width of the outflow face of each identical LID unit (in ft or m). This  parameter only applies
to LID processes  such as Porous Pavement and Vegetative Swales that use  overland flow to
convey surface runoff off of the unit. (The other LID processes, such as Bio-Retention Cells and
Infiltration Trenches  simply spill any excess captured runoff over their berms.)

% Initially Saturated
For Bio-Retention Cells this is the degree to which the unit's soil is initially filled with water (0 %
saturation corresponds to the wilting point moisture content, 100  % saturation has the moisture
content equal to the porosity). The storage zone beneath the soil zone of the cell is assumed to be
completely dry. For other types  of LIDs it corresponds to the degree to which their storage zone is
initially filled with water.

% of Impervious Area Treated
The percent of the impervious portion of the subcatchment's non-LID area  whose runoff is treated
by the LID practice.  (E.g., if rain barrels are used to capture roof runoff and roofs represent 60%
of the impervious area, then the impervious area treated is 60%). If the LID unit treats only direct
rainfall, such as with a green roof, then this value  should be  0. If the LID takes  up the entire
subcatchment then this field is ignored.

Send Outflow to Pervious Area
Select this option if the outflow from the LID  is returned onto the subcatchment's pervious area
rather than going to  the subcatchment's outlet.  An example  of where this might apply is a rain
barrel whose contents are used to irrigate a lawn area. This  field is ignored if the LID takes up the
entire subcatchment.

Detailed Report File
The name of an optional file where detailed time series results  for the LID will be written.  Click
the browse button •*  to select a file using  the standard Windows File Save dialog or click the
delete  button  to remove any detailed reporting. The detailed report file will be a tab delimited
text file that can be easily opened and viewed with any text editor or spreadsheet program (such
as Microsoft Excel) outside of SWMM.
                                           217

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C.15   Pollutant Editor
 Name
 Units
 Rain Concen.
 GW Concen.
 I8cl Concen.
 DWF Concen.
 Decay Coeff.
 Snow Only
 Co-Pollutant
 Co-Fraction
UG/L
0.0
0.0
0.0
0.0
0.0
NO
TSS
0.25
 User-assigned name of the pollutant.
The Pollutant Editor is invoked when a new pollutant object is created or an existing pollutant is
selected for editing.  It contains the following fields:
Name
The name assigned to the pollutant.
Units
The concentration units (mg/L, ug/L, or #/L (counts/L)) in which the pollutant concentration is
expressed.
Rain Concentration
Concentration of the pollutant in rain water (concentration units).
GW Concentration
Concentration of the pollutant in ground water (concentration units).
I&I Concentration
Concentration of the pollutant in any Infiltration/Inflow (concentration units).
                                             218

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DWF Concentration
Concentration of the pollutant in any dry weather sanitary flow (concentration units). This value
can be overriden for any specific node of the conveyance system by editing the node's Inflows
property.

Decay Coefficient
First-order decay coefficient of the pollutant (I/days).

Snow Only
YES if pollutant buildup occurs only when there is snow cover, NO otherwise (default is NO).

Co-Pollutant
Name of another pollutant whose runoff concentration contributes to the runoff concentration of
the current pollutant.

Co-Fraction
Fraction of the co-pollutant's runoff concentration that contributes to the runoff concentration of
the current pollutant.

An example of a co-pollutant relationship  would be where the runoff concentration of a particular
heavy metal is some fixed fraction of the runoff concentration of suspended solids. In this case
suspended solids would be declared as the co-pollutant for the heavy metal.
C16.   Snow Pack Editor

The  Snow Pack Editor is invoked when a new snow pack object is created or an existing snow
pack is  selected for editing. The editor contains a data entry field for the snow pack's name and
two tabbed pages, one for snow pack parameters and one for snow removal parameters.
                                           219

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Snow Pack Parameters Page
 Snow Pack Editor
   Snow Pack Name
                      SP1
    Snow Pack Parameters Snow Removal Parameters
Subcatchment Surface Type
Min. Melt Coeff. (in/hr/deg F)
Max. Melt Coeff. (in/hr/deg F)
Base Temperature (deg F)
Fraction Free Water Capacity
Initial Snow Depth (in)
Initial Free Water (in)
Depth at 100% Cover (in)
Plowable
0.001
0.001
32.0
0.10
0.00
0.00

Impervious
0.001
0.001
32.0
0.10
0.00
0.00
0.00
Pervious
0.001
0.001
32.0
0.10
0.00
0.00
0.00
             Fraction of Impervious Area That is Plowable:   0.5
                                                                  Help
The Parameters page of the Snow Pack Editor dialog provides snow melt parameters and initial
conditions for snow that accumulates over three different types of areas: the impervious area that
is  plowable (i.e.,  subject to snow removal), the  remaining impervious area,  and the entire
pervious area. The page contains a data entry grid which has a column for each type of area and a
row for each of the following parameters:

Min. Melt Coefficient
The degree-day snow melt coefficient that occurs on December 21. Units are either in/hr-deg F or
mm/hr-deg C.

Max. Melt Coefficient
The degree-day snow melt coefficient that occurs  on June 21. Units are either in/hr-deg F or
mm/hr-deg C. For a short term simulation of less than a week or so it is acceptable to use a single
value for both the minimum and maximum melt coefficients.
                                           220

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The minimum and maximum snow melt coefficients are used to estimate a melt coefficient that
varies by day of the year. The latter is used in the following degree-day equation to compute the
melt rate for any particular day:

    Melt Rate = (Melt Coefficient) * (Air Temperature - Base Temperature).

Base Temperature
Temperature at which snow begins to melt (degrees F or C).

Fraction Free Water Capacity
The volume of a snow pack's pore space which must fill with melted snow before liquid runoff
from the pack begins, expressed as a fraction of snow pack depth.

Initial Snow Depth
Depth of snow at the start of the simulation (water equivalent depth in inches or millimeters).

Initial Free Water
Depth of melted water held  within the pack at the start of the simulation (inches or mm). This
number should be  at or below  the product of the initial snow depth and the fraction free water
capacity.

Depth at 100% Cover
The depth of snow beyond which the entire area remains completely covered and is not subject to
any areal depletion effect (inches or mm).

Fraction of Impervious Area  That is Plowable
The fraction of impervious area that is plowable and therefore is not subject to areal depletion.
                                          221

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Snow Removal Parameters Page
   Snow Pack Name
                      Snow Removal Parameters
    Snow Pack Parameters
            Depth at which snow removal begins (mm)
            Fraction transferred out of the watershed
            Fraction transferred to the impervious area
            Fraction transferred to the pervious area
            Fraction converted into immediate melt
            Fraction moved to another subcatchrnent

            (Name)
            Note: sum of all fractions must be <= 1.0.
The Snow Removal page of the Snow Pack Editor describes how snow removal occurs within the
Plowable area of a snow pack. The following parameters govern this process:

Depth at which snow removal begins (in or mm)
Depth which must be reached before any snow removal begins.

Fraction transferred out of the watershed
The fraction of snow depth that is removed from the system (and does not become runoff).

Fraction transferred to the impervious area
The fraction of snow depth that is added to snow accumulation on the pack's impervious area.

Fraction transferred to the pervious area
The fraction of snow depth that is added to snow accumulation on the pack's pervious area.

Fraction converted to immediate melt
The  fraction of snow  depth that becomes liquid  water which runs  onto  any subcatchrnent
associated with the snow pack.
                                            222

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Fraction moved to another subcatchment
The  fraction  of snow depth  which  is  added to  the  snow accumulation  on  some  other
subcatchment. The name of the subcatchment must also be provided.

The various removal fractions must add up to 1.0 or less. If less than 1.0, then some remaining
fraction of snow depth will  be left on the surface  after all of the redistribution options are
satisfied.
C.17  Time Pattern Editor
 Time Pattern Editor
   Name
Type
    DWF
 HOURLY
   Description
    Global hourly DWF pattern
   Multipliers
12AM
1AM
2AM
3AM
4AM
SAM
GAM
.0151
.01373
.01812
.01098
.01098
.01922
.02773 »
The Time Pattern Editor is invoked when a new time pattern object is created or an existing time
pattern is selected for editing. The editor contains that following data entry fields:

Name
Enter the name assigned to the time pattern.

Type
Select the type of time pattern being specified.

Description
You can provide an optional comment or description for the time pattern. If more than one line is
needed, click the & button to launch a multi-line comment editor.
                                           223

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Multipliers
Enter a value for each multiplier. The number and meaning of the multipliers changes with the
type of time pattern selected:
    •   MONTHLY      One multiplier for each month of the year.

    •   DAILY        One multiplier for each day of the week.

    •   HOURLY       One multiplier for each hour from 12 midnight to 11 PM.

    •   WEEKEND      Same as for HOURLY except applied to weekend days.
       In order to maintain  an average dry weather flow or pollutant concentration at its
       specified value (as entered on the Inflows Editor), the  multipliers for a pattern should
       average to 1.0.
C.18   Time Series Editor
Time Series Editor

Time Series Name
82309
Description

Direct Inflow at Node 82309 gjj)
HI Use external data file named below
s
3 Enter time series data in the table below
^lo dates means times are relative to start of simulation.
Date Time
(M/D/T) (H:M) Value
0:00 0
0:15 ~40~~
3:00 40
3:15 0
12:00 0



[ | V
View...

r------ |

Cancel

Help

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The Time Series Editor is invoked whenever a new time series object is created or an existing
time series is selected for editing. To use the Time Series Editor:

    l.  Enter values for the following standard items:
        Name         Name of the time series.
        Description     Optional comment or description of  what the time series represents.
                       Click the ^ button to launch a multi-line comment editor if more than
                       one line is  needed.
    2.  Select whether to use an external file as the source of the data or to enter the data directly
        into the form's data entry grid.

    3.  If the external file option is selected, click the « button to locate the file's name. The
        file's contents must be formatted in the same manner as  the direct data entry option
        discussed below. See the description of Time Series Files in Section 11.6 for details.
    4 .  For direct data entry, enter  values in the data entry grid as follows:
        Date Column    Optional date (in month/day/year format) of the time series values (only
                      needed at points in time where a new date occurs).
        Time Column    If dates are used, enter the military time of day for each time series value
                       (as hours:minutes or decimal hours). If dates are not used, enter time as
                      hours since the start of the simulation.
        Value Column   The time series' numerical values.
        A graphical plot of the data in the grid can be viewed in a separate window by clicking
        the View button. Right clicking over the grid will make a popup Edit menu appear. It
        contains commands to cut,  copy, insert, and paste selected cells in the grid as well as
        options to insert or delete a row.
    5.  Press OK to accept the time series or Cancel to cancel your edits.

Note that there are two methods for describing the occurrence time  of time series  data:
    •    as calendar date/time of day (which  requires that at least one date, at the start of the
        series, be entered in the Date column)
    •    as elapsed hours since the start of the simulation (where the Date column remains empty).
                                           225

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C.19   Title/Notes Editor
    Project Title/Notes
in  x
  Example 3
  Use  of Rule-Based Pump Controls
  and  Dry Weather  Flow Patterns

     Jse title line as header for printing
The  Title/Notes editor is invoked  when  a project's Title/Notes data category is  selected for
editing. As  shown below,  the editor contains a multi-line  edit field where a description of a
project can be entered. It also contains a check box used to indicate whether or not the first line of
notes should be used as a header for printing.
                                           226

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C.20   Transect Editor
 Transect Editor
   Transect Name
Description
    91
      View...

1
2
3
4
5
6
7
8
9
10
Station
(ft)
0
50
55
100
110
150




Elevation
(ft)
5
4
1
0
3
5




A









V
     OK
                                       Property
                                       Roughness:
                                        Left Bank
                                        Right Bank
                                        Channel
                                       Bank Stations:
                                        Stations
                                        Elevations
                                        Meander
                        Value
                        0.04
                        0.04
                        0.04
                        0.0
                        799
                         1.2
Cancel
Help
The Transect Editor is invoked when a new transect object is created or an existing transect is
selected for editing. It contains the following data entry fields:

Name
The name assigned to the transect.

Description
An optional comment or description of the transect.

Station/Elevation Data Grid
Values of distance from the left side of the channel along with the corresponding elevation of the
channel bottom as one moves across the channel from left to right, looking in the downstream
direction. Up to 1500 data values can be entered.

Roughness
Values of Manning's roughness for the left overbank, right overbank, and main channel portion of
the transect. The overbank roughness values can be zero if no overbank exists.
                                            227

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Bank Stations
The distance values appearing in the Station/Elevation grid that mark the end of the left overbank
and the start of the right overbank. Use 0 to denote the absence of an overbank.

Modifiers
•   The  Stations modifier is a factor  by  which the distance between each  station  will  be
    multiplied when the transect data is processed by SWMM. Use a value of 0 if no such factor
    is needed.
•   The Elevations modifier is a constant value that will be added to each elevation value.
•   The Meander modifier is the ratio  of the  length of a meandering main channel to the length of
    the overbank area that surrounds it. This modifier is  applied to all  conduits that use this
    particular  transect for  their cross section. It assumes that the  length supplied for these
    conduits is that of the longer main channel. SWMM will use the shorter overbank length in its
    calculations while increasing the main channel roughness to  account for its longer length. The
    modifier is ignored if it is left blank or set to 0.

Right-clicking over the Data Grid will make a popup Edit menu appear. It contains commands to
cut, copy, insert, and paste selected cells in the grid as well as options to insert or delete a row.

Clicking the View button will bring up a window that illustrates the shape of the transect cross
section.
C.21    Treatment Editor
Treatment Editor for Node 16















Pollutant
TSS
Lead


Treatment Expression
C = 0.523"TSS"0.5XFLOW"1.2



Treatment expressions have the general form:
A
R = f(P, R_P, V)
or


C = f(P, R_P, V)
where:

^3
R = fractional removal.
C = outlet concentration.
P = one or more pol lut ant name s ,
R P = one or more pollutant removals
(prepend R to pollutant name) ,
V = one or more process variables


I OK j Cancel


Help














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The Treatment Editor is invoked whenever the Treatment property of a node is selected from the
Property Editor. It displays a list of the project's pollutants with an edit box next to each as shown
below. Enter  a valid treatment expression  in the  box next to each pollutant  which receives
treatment. Refer to the Treatment topic in Section 3.3 to learn what constitutes a valid treatment
expression.
C.22   Unit Hydrograph Editor
 Unit Hydrograph Editor
   Name of UH Group
   Rain Gage Used
UH1
Gagel
   Hydrographs For:
All Months (")
                                                -
L
I nit Hydrographs
Initial Abstraction Depth

Response
Short-Term
Medium-Term
Long-Term
R
0.20
0.10
0.06

T
2
6
12

K
2
2
2
R = fraction of rainfall that becomes l&l
T = time to hydrograph peak (hours)
K = falling limb duration /' rising limb duration
   Months with UH data have a (*) next to them.
                                       Help
The Unit Hydrograph Editor is invoked whenever a new unit hydrograph object is created or an
existing one is selected for editing. It is used to specify the shape parameters and rain gage for a
group of triangular unit hydrographs. These hydrographs are used to compute rainfall-dependent
infiltration/inflow (RDII) flow at selected nodes of the drainage system. A UH group can contain
up to  12 sets of unit hydrographs (one for each month of the year), and each set can consist of up
to 3  individual  hydrographs  (for  short-term, intermediate-term,  and  long-term  responses,
respectively) as well as parameters that describe any initial abstraction losses. The editor contains
the following data entry fields:
                                           229

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Name of UH Group
Enter the name assigned to the UH Group.

Rain Gage Used
Type in (or select from the dropdown list) the name of the rain gage that supplies rainfall data to
the unit hydrographs in the group.

Hydrographs For:
Select  a month from the dropdown list box for which hydrograph parameters will be defined.
Select  All Months to specify a default set of hydrographs that apply to all months of the year.
Then select specific months  that need to have special hydrographs defined. Months listed with a
(*) next to them have had hydrographs assigned to them.

Unit Hydrographs
Select this tab to provide the R-T-K shape  parameters for each set of unit hydrographs in selected
months of the year. The first row  is used to specify  parameters for  a  short-term response
hydrograph (i.e., small value of T), the second for a medium-term response hydrograph, and the
third for a long-term response hydrograph (largest value of T). It is not required that all three
hydrographs be defined and  the sum of the three R-values do not have to equal 1. The shape
parameters for each UH consist of:
    •   R: the fraction of rainfall volume that enters the sewer system
    •   T: the time from the  onset of rainfall to the peak of the UH in hours
    •   K: the ratio of time to recession of the UH to the time to peak

Initial Abstraction Depth
Select  this tab to provide parameters that describe how  rainfall will be reduced by any initial
abstraction depth available  (i.e., interception  and depression storage) before it is processed
through the unit hydrographs defined for a specific month of the year. Different initial abstraction
parameters can be assigned to each of the three unit hydrograph responses. These parameters are:
    •   Dmax: the maximum depth of initial abstraction available (in rain depth units)

    •   Dree:  the rate at which any  utilized initial abstraction is made available again (in rain
       depth units per day)
    •   Do:  the  amount of initial abstraction that has already been utilized  at the start of the
       simulation (in rain depth units).

If a grid cell is left empty its corresponding parameter value is assumed to be 0. Right-clicking
over a  data entry grid will make a popup Edit menu appear.  It contains commands to cut, copy,
and paste text to or from selected cells in the grid.
                                           230

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APPENDIX D - COMMAND LINE SWMM
D.1    General Instructions

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

    swmm5 inpfile  rptfile  outfile

where inpfile is the name of the input file, rptfile is the name of the output report file, and
outfile is the name of an optional binary output file. The latter stores all time series results in
a special binary format that will require a separate post-processor program for viewing. If no
binary output file name is supplied then all time series results will appear in the report file. As
written, the above command assumes that you are working in the directory in which EPA SWMM
was installed or that this directory has been added to the PATH variable in your user profile (or
the autoexec.bat file in older versions of Windows). Otherwise full pathnames for the executable
swmm5.exe and the files on the command line must be used.
D.2    Input File Format

The input file for command line SWMM has the same format as the project file used by the
Windows version of the program. Figure D-l illustrates an example SWMM 5 input file. It is
organized in sections, where each section begins with a  keyword enclosed in brackets. The
various keywords are listed below.
       [TITLE]
       [OPTIONS]
       [REPORT]
       [FILES]

       [RAINGAGES]
       [HYDROGRAPHS]
       [EVAPORATION]
       [TEMPERATURE]

       [SUBCATCHMENTS]
       [SUBAREAS]
       [INFILTRATION]
       [LID_CONTROLS]
       [LIDJJSAGE]
       [AQUIFERS]
       [GROUNDWATER]
       [SNOWPACKS]

       [JUNCTIONS]
       [OUTFALLS]
project title
analysis options
output reporting instructions
interface file options

rain gage information
unit hydrograph data used to construct RDII inflows
evaporation data
air temperature and snow melt data

basic subcatchment information
subcatchment impervious/pervious sub-area data
subcatchment infiltration parameters
low impact development control information
assignment of LID controls to subcatchments
groundwater aquifer parameters
subcatchment groundwater parameters
subcatchment snow pack parameters

junction node information
outfall node information
                                         231

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        [DIVIDERS]
        [STORAGE]
        [CONDUITS]
        [PUMPS]
        [ORIFICES]
        [WEIRS]
        [OUTLETS]
        [XSECTIONS]
        [TRANSECTS]
        [LOSSES]
        [CONTROLS]

        [POLLUTANTS]
        [LANDUSES]
        [COVERAGES]
        [BUILDUP]
        [WASHOFF]
        [TREATMENT]

        [INFLOWS]
        [DWF]
        [PATTERNS]
        [RDII]
        [LOADINGS]

        [CURVES]
        [TIMESERIES]
flow divider node information
storage node information
conduit link information
pump link information
orifice link information
weir link information
outlet link information
conduit, orifice, and weir cross-section geometry
transect geometry for conduits with irregular cross-sections
conduit entrance/exit losses and flap valves
rules that control pump and regulator operation

pollutant information
land use categories
assignment of land uses to subcatchments
buildup functions for pollutants and land uses
washoff functions for pollutants and land uses
pollutant removal functions at conveyance system nodes

external hydrograph/pollutograph inflow at nodes
baseline dry weather sanitary inflow at nodes
periodic variation in dry weather inflow
rainfall-dependent I/I information at nodes
initial pollutant loads on subcatchments

x-y tabular data referenced in other sections
time series data referenced in other sections
The sections can appear in any arbitrary order in the input file, and not all sections must be
present. Each section can contain one or more lines of data. Blank lines may appear anywhere in
the file. A semicolon (;) can be used to indicate that what follows on the line is a comment, not
data. Data items can appear in any column of a line. Observe how in Figure D-l these features
were used to create a tabular appearance for the data, complete with column headings.

Section keywords can appear in mixed lower and upper case, and only  the first four characters
(plus the open bracket) are used to distinguish one keyword from another (e.g., [DIVIDERS] and
[Divi] are equivalent).  An option is available in the [OPTIONS] section to choose flow units
from among cubic feet per second (CFS), gallons per minute (GPM), million  gallons per day
(MGD), cubic meters per second (CMS), liters per second, (LPS),  or million  liters  per day
(MLD). If cubic feet or gallons are chosen for flow units, then US units are used for all other
quantities. If cubic meters or liters are chosen, then metric  units apply to all other quantities. The
default flow units are CFS.

A detailed description of the data in each section of the input file will now be given. When listing
the format  of a line of data, mandatory keywords are shown in boldface while optional items
appear in parentheses. A list of keywords separated by a slash (YES/NO) means that only one of
the words should appear in the data line.
                                           232

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[TITLE]
Example SWMM Project
[OPTIONS]
FLOWJJNITS
INFILTRATION
FLOW_ROUTING
START_DATE
START_TIME
END_TIME
WET_STEP
DRY_STEP
ROUTING STEP
CFS
GREEN_AMPT
KINWAVE
8/6/2002
10: 00
18: 00
00:15:00
01:00:00
00:05:00
[RAINGAGES]
;;Name     Format      Interval  SCF  DataSource  SourceName

GAGE1      INTENSITY   0:15       1.0  TIMESERIES  SERIES1

[EVAPORATION]
CONSTANT   0.02

[SUBCATCHMENTS]
;;Name  Raingage Outlet   Area   %Imperv   Width  Slope

AREA1   GAGE1    NODE1    2       80.0      800.0  1.0
AREA2   GAGE1    NODE2    2       75.0      50.0   1.0

[SUBAREAS]
;;Subcatch  N_Imp  N_Perv  S_Imp  S_Perv  %ZER  RouteTo

AREA1       0.2    0.02      0.02    0.1     20.0  OUTLET
AREA2       0.2    0.02      0.02    0.1     20.0  OUTLET

[INFILTRATION]
;;Subcatch   Suction   Conduct   InitDef

AREA1        4.0       1.0        0.34
AREA2        4.0       1.0        0.34

[JUNCTIONS]
;;Name     Elev

NODE1      10.0
NODE2      10.0
NODES      5 . 0
NODE4      5.0
NODE6      1.0
NODE?      2.0

[DIVIDERS]
;;Name     Elev   Link    Type   Parameters

NODES      3.0    C6      CUTOFF 1.0
          Figure D-l. Example SWMM project file (continued on next page).
                                      233

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[CONDUITS]
; ; Name Nodel Node2
Cl NODE1 NODE3
C2 NODE2 NODE4
C3 NODE3 NODES
C4 NODE4 NODES
C5 NODES NODE6
C6 NODES NODE?
[XSECTIONS]
; ; Link Type
Cl RECT OPEN
C2 RECT OPEN
C3 CIRCULAR
C4 RECT OPEN
C5 PARABOLIC
C6 PARABOLIC
[POLLUTANTS]
; ; Name Units Cppt Cgw
TSS MG/L 0 0
Lead UG/L 0 0
[LANDUSES]
RESIDENTIAL
UNDEVELOPED
[WASHOFF]
;;Landuse Pollutant
RESIDENTIAL TSS
UNDEVELOPED TSS
[COVERAGES]
; ; Subcatch Landuse
AREA1 RESIDENTIAL
AREA2 RESIDENTIAL
[TIMESERIES]
; Rainfall time series
SERIES1 0:0 0.1
SERIES1 0:45 0.1
[REPORT]
INPUT YES
SUBCATCHMENTS ALL
NODES ALL
LINKS C4 C5

Length N Zl Z2 QO
800 0.01 000
800 0.01 000
400 0.01 000
400 0.01 000
600 0.01 000
400 0.01 000

Gl G2 G3 G4
0.5 1 0 0
0.5 1 0 0
1.0 000
1.0 1.0 0 0
1.5 2.0 0 0
1.5 2.0 0 0

Cii Kd Snow CoPollut CoFrac
0 0
0 0 NO TSS 0.20




Type Coeff Expon SweepEff
EMC 23.4 0 0
EMC 12.1 0 0

Pent Landuse Pent
80 UNDEVELOPED 20
55 UNDEVELOPED 45


0: 15 1.0 0:30 0.5
1: 00 0.0 2:00 0.0




C6

















t






BMPEff
0
0













Figure D-l. Example SWMM project file (continued from previous page)
                                234

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Section:   [TITLE]

Purpose:  Attaches a descriptive title to the problem being analyzed.

Format:   Any number of lines may be entered. The first line will be used as a page header in
          the output report.


Section:   [OPTIONS]

Purpose:  Provides values for various analysis options.
Format:   FLOWJJNITS
          INFILTRATION
          FLOW_ROUTING
          LINK_OFFSETS
          FORCE_MAIN_E QUATION
          IGNORE_RAINFALL
          IGNORE_SNOWMELT
          IGNORE_GROUNDWATER
          IGNORE_ROUTING
          IGNORE_QUALITY
          ALLOW_PONDING
          SKIP_STEADY_STATE
          START_DATE
          START_TIME
          END_DATE
          END_TIME
          RE PORT_S TART_DATE
          RE PORT_S TART_T IME
          SWEEP_START
          SWEEP_END
          DRY_DAYS
          REPORT_STEP
          WET_STEP
          DRY_STEP
          ROUTING_STEP
          LENGTHENING_STEP
          VARIABLE_STEP
          INERTIAL_DAMPING
          NORMAL_FLOW_LIMITED
          MIN_SURFAREA
          MIN_SLOPE
          TEMPOIR
CFS /  GPM  / MGD /  CMS  /  LPS  / MLD
HORTON / GREEN_AMPT /  CURVE_NUMBER
STEADY / KINWAVE /  DYNWAVE
DEPTH  / ELEVATION
H-W /  D-W
YES /  NO
YES /  NO
YES /  NO
YES /  NO
YES /  NO
YES /  NO
YES /  NO
month/day/year
hours:minutes
month/day/year
hours: minutes
month/day/year
hours: minutes
month/day
month/day
days
hours minutes: seconds
hours minutes: seconds
hours minutes: seconds
seconds
seconds
value
NONE / PARTIAL  / FULL
SLOPE  / FROUDE  / BOTH
value
value
directory
Remarks:  FLOW_UNITS makes a choice of flow units. Selecting a US flow unit means that all
          other quantities will be expressed in US units, while choosing a metric flow unit will
          force all quantities to be expressed in metric units. The default is CFS.
                                       235

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INFILTRATION selects a model for computing infiltration of rainfall into the upper
soil zone of subcatchments. The default model is HORTON.

FLOW_ROUTING  determines which  method is used to route flows through the
drainage system. STEADY refers to sequential steady state routing (i.e. hydrograph
translation), KINWAVE  to kinematic wave  routing,  DYNWAVE  to dynamic wave
routing. The default routing method is KINWAVE.

LINK_OFFSETS determines the convention used to specify the position of a link
offset above the  invert of its connecting node. DEPTH indicates that offsets are
expressed as the distance between the node  invert and the link while ELEVATION
indicates that the absolute elevation of the offset is used. The default is DEPTH.

FORCE_MAIN_EQUATION  establishes whether the Hazen-Williams (H-W)  or the
Darcy-Weisbach  (D-W) equation will be  used  to  compute  friction losses  for
pressurized flow in conduits that have been assigned a Circular Force Main cross-
section shape. The default is H-W.

IGNORE_RAINFALL is set to YES if all rainfall data and runoff calculations should
be ignored. In this case  SWMM only performs flow and pollutant routing based on
user-supplied direct and dry weather inflows.  The default is NO.

IGNORE_SNOWMELT is set to YES if snowmelt calculations should be ignored when
a project file contains snow pack objects. The default is NO.

IGNORE_GROUNDWATER is set  to  YES if groundwater calculations should be
ignored when a project file contains aquifer objects. The default is NO.

IGNORE_ROUTING is set to YES if only runoff should be computed even if the
project contains drainage system links and nodes. The default is NO.

IGNORE_QUALITY is set to YES if pollutant washoff, routing, and treatment should
be ignored in a project that has pollutants defined. The default is NO.

ALLOW_PONDING determines whether excess water is allowed to collect atop nodes
and be re-introduced into the  system as conditions permit. The default is NO ponding.
In order for ponding to actually occur at a particular node, a non-zero value  for its
Ponded Area attribute must be used.

SKIP_STEADY_STATE should be set to YES if flow routing computations should
be skipped during steady state periods of a  simulation during which the last set of
computed flows will be used. A time  step is  considered to be in steady state if there
has been no significant change in external inflows, storage volumes, and either node
water depths  (for dynamic  wave routing)  or conduit flows  (for other  forms of
routing). The default for this option is NO.

START_DATE is the  date when the  simulation begins.  If not supplied,  a date of
1/1/2002 is used.
                              236

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START_TIME is the time of day on the starting date when the simulation begins. The
default is 12 midnight (0:00:00).

END_DATE is the date when the simulation is to end. The default is the start date.

END_TIME is the time of day on the ending date when the simulation will end. The
default is 24:00:00.

REPORT_START_DATE is the date when reporting of results is to begin. The default
is the simulation start date.

REPORT_START_TIME is the time of day on the report starting date when reporting
is to begin. The default is the simulation start time of day.

SWEEP_START is the day of the year (month/day) when street sweeping operations
begin. The default is 1/1.

SWEEP_END is the day of the year (month/day) when street sweeping operations
end. The default is 12/31.

DRY_DAYS is the number of days with no rainfall prior to the start of the simulation.
The default is 0.

REPORT_STEP is the time interval for reporting of computed results. The default is
0:15:00.

WET_STEPis the time step length  used to compute runoff from subcatchments
during periods of rainfall or when ponded water  still remains on the surface. The
default is 0:05:00.

DRY_STEP  is  the  time step length used for  runoff computations (consisting
essentially of pollutant buildup) during periods when there  is no rainfall  and no
ponded water. The default is 1:00:00.

ROUTING_STEP is the time step length in seconds used for routing flows  and water
quality  constituents through the  conveyance system.  The  default is  600 sec (5
minutes) which should be reduced if using dynamic wave routing. Fractional values
(e.g., 2.5) are permissible as are values entered in hours:minutes:seconds format.

LENGTHENING_STEP is a time step, in seconds, used to lengthen conduits under
dynamic wave routing,  so that they meet the Courant stability criterion under full-
flow conditions (i.e., the travel time of a wave will not be smaller  than the specified
conduit lengthening time step). As this value is decreased, fewer conduits will require
lengthening. A value of 0 (the default) means that no conduits will be lengthened.

VARIABLE_STEP is a safety factor applied to a variable  time step computed for
each time period under dynamic  wave  flow  routing.  The  variable  time  step is
computed so as to satisfy the Courant stability criterion for each conduit and yet not
exceed the  ROUTING_STEP  value.  If the  safety  factor is  0  (the default), then no
variable time step is used.
                               237

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           INERTIAL_DAMPING indicates how  the  inertial terms  in  the Saint Venant
           momentum equation will be handled under dynamic wave flow routing. Choosing
           NONE  maintains these terms  at their  full value  under  all conditions.  Selecting
           PARTIAL will reduce the terms as flow comes closer to being critical (and ignores
           them when flow is supercritical). Choosing FULL will drop the terms altogether.

           NORMAL_FLOW_LIMI TED  specifies which condition  is checked to  determine if
           flow in a conduit is supercritical and should thus be limited to the normal flow. Use
           SLOPE to check if the water surface slope is greater than the conduit slope, FROUDE
           to check if the Froude number is greater than 1.0, or BOTH to check both conditions.
           The default is BOTH.

           MIN_SURFAREA is a minimum surface area used at nodes when computing changes
           in water depth under dynamic wave routing. If 0 is entered, then the default value of
           12.566 ft2 (i.e., the area of a 4-ft diameter manhole) is used.

           MIN_SLOPE is the minimum value allowed for a conduit's slope (%). If zero (the
           default) then no minimum  is imposed (although  SWMM uses a lower limit  on
           elevation drop of 0.001 ft (0.00035 m) when computing a conduit slope).

           TEMPDIR provides the name of a file directory (or folder) where SWMM writes its
           temporary files.  If the directory name contains spaces then it should be placed within
           double quotes. If no directory is specified, then the temporary files are written to the
           current directory that the user is working in.
Section:    [REPORT]

Purpose:   Describes the contents of the report file that is produced.

Formats:   INPUT           YES  / NO
           CONTINUITY     YES  / NO
           FLOWS TATS      YES  / NO
           CONTROLS        YES  / NO
           SUBCATCHMENTS ALL  / NONE / 
           NODES           ALL  / NONE / 
           LINKS           ALL  / NONE / 

Remarks:  INPUT specifies whether or not a summary of the input data should be provided in
           the output report. The default is NO.

           CONTINUITY specifies whether continuity checks should be reported or not. The
           default is YES.

           FLOWS TATS specifies whether summary flow statistics should be reported or not.
           The default is YES.
                                        238

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          CONTROLS specifies whether all control actions taken during a simulation should be
          listed or not. The default is NO.

          SUBCATCHMENTS gives a list of subcatchments whose results are to be reported.
          The default is NONE.

          NODES gives a list of nodes whose results are to be reported. The default is NONE.

          LINKS gives a list of links whose results are to be reported. The default is NONE.

          The SUBCATCHMENTS, NODES, and LINKS lines can be repeated multiple times.
Section:   [FILES]

Purpose:  Identifies optional interface files used or saved by a run.

Formats:  USE /  SAVE RAINFALL    Fname
          USE /  SAVE RUNOFF       Fname
          USE /  SAVE HOTSTART    Fname
          USE /  SAVE RDII         Fname
          USE   INFLOWS             Fname
          SAVE  OUTFLOWS           Fname

Remarks:  Fname    name of interface file.

          Refer to Section 11.7 for a description of interface files. Rainfall, Runoff, and RDII
          files can either be used or saved in a run, but not both. A run can both use and save a
          Hot Start file (with different names).
Section:   [RAINGAGES]

Purpose:  Identifies each rain gage that provides rainfall data for the study area.

Formats:  Name  Form  Intvl  SCF TIMESERIES Tseries
          Name  Form  Intvl  SCF FILE  Fname Sta  Units

Remarks:  Name     name assigned to rain gage.
          Form     form of recorded rainfall, either INTENSITY,  VOLUME or
                    CUMULATIVE.
          Intvl    time interval between gage readings in decimal hours or hours:minutes
                    format (e.g., 0:15 for 15-minute readings).
          SCF      snow catch deficiency correction factor (use 1.0 for no adjustment).
          Tseries name of time series in [TIMESERIES] section with rainfall data.
          Fname    name of external file with rainfall data. Rainfall files are discussed in
                    Section 11.3.
                                        239

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           Sta       name of recording station used in the rain file.
           Units    rain depth units used in the rain file, either IN (inches) or MM
                     (millimeters).
Section:    [EVAPORATION]

Purpose:   Specifies how daily evaporation rates vary with time for the study area.

Formats:   CONSTANT    evap
           MONTHLY     evapl  evap2  . .  .  evap!2
           TIMESERIES Tseries
           TEMPERATURE
           FILE          (panl  pan2  . . .  pan!2)
           RECOVERY    patternID
           DRY_ONLY    NO / YES

Remarks:  evap      constant evaporation rate (in/day or mm/day).
           evapl     evaporation rate in January (in/day or mm/day).

           evap 12   evaporation rate in December (in/day or mm/day).
           Tseries  name of time series in [TIMESERIES] section with evaporation data.
           panl      pan coefficient for January.

           panl 2     pan coefficient for December.
           pat ID     name of a monthly time pattern

           Use only one  of the above  formats (CONSTANT,   MONTHLY,   TIMESERIES,
           TEMPERATURE,  or  FILE).  If no  [EVAPORATION]  section  appears,   then
           evaporation is assumed to be 0.

           TEMPERATURE indicates that evaporation rates will be computed from the daily air
           temperatures contained in an external climate file whose name is provided in the
           [TEMPERATURE] section (see below). This  method also uses the site's latitude,
           which can also be specified in the [TEMPERATURE] section.

           FILE indicates that evaporation data will be read directly from the same external
           climate file used for air temperatures as specified  in the  [TEMPERATURE] section
           (see below).

           RECOVERY identifies an optional monthly time pattern of multipliers used to modify
           infiltration recovery rates during dry periods. For example, if the normal infiltration
           recovery rate was 1% during a specific time period and a pattern factor of 0.8 applied
           to this period, then the actual recovery rate would be 0.8%.

           DRY_ONLY  determines  if  evaporation only  occurs  during periods with no
           precipitation. The default is NO.
                                        240

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Section:    [TEMPERATURE]

Purpose:   Specifies  daily  air temperatures,  monthly wind speed,  and  various  snowmelt
           parameters for the study  area. Required only when snowmelt is being modeled or
           when evaporation rates are computed from daily temperatures or are read from an
           external climate file.

Formats:   TIMESERIES  Tseries
           FILE   Fname  (Start)
          WINDSPEED
          WINDSPEED
MONTHLY  si  s2
FILE
...  sll  s!2
           SNOWMELT
           ADC  IMPERVIOUS
           ADC  PERVIOUS
       Stamp  ATIwt
       f.O   f.l  ...  f.
       f.O   f.l  ...  f.
       RNM   Elev
       ?   f. 9
       ?   f. 9
Lat  DTLong
Remarks:  Tseries name of time series in [TIMESERIES] section with temperature data.
           Fname    name of external Climate file with temperature data.
           Start    date to begin reading from the file in month/day/year format (default is
                     the beginning of the file).
           si        average wind speed in January (mph or km/hr).

           si 2       average wind speed in December (mph or km/hr).
           Stemp    air temperature at which precipitation falls as snow (deg F or C).
           ATIwt    antecedent temperature index weight (default is 0.5).
           RNM       negative melt ratio (default is 0.6).
           El ev     average elevation of study area above mean sea level (ft or m) (default is
                     0).
           La t       latitude of the study area in degrees North (default is 50).
           DTLong   correction, in minutes of time, between true solar time and the standard
                     clock time (default is 0).
           f. 0       fraction of area covered by snow when ratio of snow depth to depth at
                     100% cover is 0.

           f. 9       fraction of area covered by snow when ratio of snow depth to depth at
                     100% cover is 0.9.

           Use the TIMESERIES line to read air temperature from a time series or the FILE
           line to read it from an external Climate file. Climate files  are discussed in Section
           11.4.  If neither format is used, then air temperature remains constant at 70 degrees F.

           Wind speed  can be  specified  either by  monthly average values or by the  same
           Climate file used for air temperature. If neither option appears, then wind speed is
           assumed to be 0.

           Separate Areal Depletion Curves (ADC) can be defined for impervious and pervious
           sub-areas. The ADC parameters will default to  1.0 (meaning no depletion) if no data
           are supplied for a particular type of sub-area.
                                         241

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Section:   [SUBCATCHMENTS]

Purpose:  Identifies each subcatchment within the study area. Subcatchments are land area units
          which generate runoff from rainfall.

Format:   Name  Rgage OutID  Area %Imperv  Width  Slope  Clength  (Spack)

Remarks:  Name      name assigned to subcatchment.
          Rgage    name of rain gage in [RAINGAGES] section assigned to subcatchment.
          OutID    name of node or subcatchment that receives runoff from subcatchment.
          Area      area of subcatchment (acres or hectares).
          %Imperv  percent imperviousness of subcatchment.
          Wid th    characteristic width of subcatchment (ft or meters).
          Slope    subcatchment slope (percent).
          Clength  total curb length (any length units).
          Spack    name of snow pack object (from [SNOWPACKS] section) that
                     characterizes snow accumulation and melting over the subcatchment.
Section:   [SUBAREAS]

Purpose:  Supplies information about pervious and impervious areas for each subcatchment.
          Each subcatchment can consist of a pervious sub-area, an impervious sub-area with
          depression storage, and an impervious sub-area without depression storage.

Format:   Subcat   Nimp   Nperv   Simp   Sperv   %Zero   (RouteTo  %Rted)

Rem arks:  Subcat   subcatchment name.
          Nimp     Manning's n for overland flow over the impervious sub-area.
          Nperv   Manning's n for overland flow over the pervious sub-area.
          Simp     depression storage for impervious sub-area (inches or mm).
          Sperv   depression storage for pervious sub-area (inches or mm).
          %Zero   percent of impervious area with no depression storage.
          RouteTo Use IMPERVIOUS if pervious area runoff runs onto impervious area,
                    PERVIOUS if impervious runoff runs onto pervious area, or OUTLET if
                    both areas drain to the subcatchment's outlet (default = OUTLET).
          %Rted   Percent of runoff routed from one type of area to another (default = 100).
                                        242

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Section:    [INFILTRATION]

Purpose:   Supplies infiltration parameters for each subcatchment. Rainfall lost to infiltration
           only occurs over the pervious sub-area of a subcatchment.

Formats:   Subcat   MaxRate  MinRate  Decay  DryTime   Maxlnf
           Subcat   Suction  Conduct  InitDef
           Subcat   CurveNo  Conduct  DryTime

Rem ar ks:   Subcat   subc atchment name.

           For Horton Infiltration:
           MaxRate  Maximum infiltration rate on Horton curve (in/hr or mm/hr).
           MinRate  Minimum infiltration rate on Horton curve (in/hr or mm/hr).
           Decay    Decay rate constant of Horton curve (1/hr).
           DryTime  Time it takes for fully saturated soil to dry (days).
           Maxlnf   Maximum infiltration volume possible (0 if not applicable) (in or mm).

           For Green-Ampt Infiltration:
           Suction  Soil capillary suction (in or mm).
           Conduct  Soil saturated hydraulic conductivity (in/hr or mm/hr).
           Ini tDef  Initial soil moisture deficit (volume of voids / total volume).

           For Curve-Number Infiltration:
           CurveNo  SCS Curve Number.
           Conduct  Soil saturated hydraulic conductivity (in/hr or mm/hr)
                     (This property has been deprecated and is no longer used.)
           DryTime  Time it takes for fully saturated soil to dry (days).
Section:    [AQUIFERS]

Purpose:   Supplies parameters  for each unconfined groundwater aquifer in the  study area.
           Aquifers consist of two zones - a lower saturated zone and an upper  unsaturated
           zone.

Formats:   Name For WP FC  K Ks  Ps  UEF  LED  GWR  BE  WTE UMC

Remarks:  Name  name assigned to aquifer.
           For    soil porosity (volumetric fraction).
           WP     soil wilting point (volumetric fraction).
           FC     soil field capacity (volumetric fraction).
           K      saturated hydraulic conductivity (in/hr or mm/hr).
           Ks     slope of the logarithm of hydraulic conductivity versus moisture deficit (i.e.,
                  porosity minus moisture content) curve (in/hr or mm/hr).
           Ps     slope of soil tension versus moisture content curve (inches or mm).
           UEF    fraction of total evaporation available for evapotranspiration in the upper
                  unsaturated zone.
                                         243

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           LED   maximum depth into the lower saturated zone over which evapotranspiration
                  can occur (ft or m).
           GWR   rate of percolation from saturated zone to deep groundwater when water table
                  is at ground surface (in/hr or mm/hr).
           BE     elevation of the bottom of the aquifer (ft or m).
           WTE   water table elevation at start of simulation (ft or m).
           UMC   unsaturated zone moisture content at start of simulation (volumetric fraction).
Section:    [GROUNDWATER]

Purpose:   Supplies parameters that determine the rate of groundwater flow between the aquifer
           underneath a subcatchment and a node of the conveyance system.

Formats:   Subcat  Aquifer Node  Surf El  Al  Bl  A2  B2  A3  TW  (H*)

Remarks:  Subcat    subcatchment name.
           Aqui fer  name of groundwater aquifer underneath the subcatchment.
           Node      name of node in conveyance system exchanging groundwater with
                      aquifer.
           Surf El    surface elevation of subcatchment (ft or m).
           Al         groundwater flow coefficient (see below).
           Bl         groundwater flow exponent (see below).
           A2         surface water flow coefficient (see below).
           B2         surface water flow exponent (see below).
           A3         surface water - groundwater interaction coefficient (see below).
           TW         fixed depth of surface water at receiving node (ft or m) (set to zero if
                      surface water depth will vary as computed by flow routing).
           H *         groundwater table height which must be reached before any flow occurs
                      (ft or m). Leave blank to use the height of the receiving node's invert
                      above the aquifer bottom.

           The  flow coefficients  are  used in  the  following  equation that  determines  a
           groundwater flow rate based on groundwater and surface water  elevations:
Qgw  =  Al (Hgw  -
                                 Bl
                                    - A2 (Hsw  -
+ A3HgwHsw
           where:
           Qgw  =  groundwater flow (cfs per acre or cms per hectare),
           Hgw  =  height of saturated zone above bottom of aquifer (ft or m),
           HSW  =  height of surface water at receiving node above aquifer bottom (ft or m),
           H*   =  threshold groundwater table height (ft or m).
                                         244

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Section:   [SNOWPACKS]

Purpose:  Specifies parameters that govern  how  snowfall accumulates  and melts on the
          plowable, impervious and pervious surfaces of subcatchments.

Formats:  Name   PLOWABLE    Cmin   Cmax   Tbase  FWF  SDO   FWO   SNNO
          Name   IMPERVIOUS  Cmin   Cmax   Tbase  FWF  SDO   FWO   SD100
          Name   PERVIOUS    Cmin   Cmax   Tbase  FWF  SDO   FWO   SD100
          Name   REMOVAL Dplow  Fout Fimp  Fperv Fimelt  (Fsub Scatch)

Remarks: Name      name assigned to snowpack parameter set.
          Cmin      minimum melt coefficient (in/hr-deg F or mm/hr-deg C).
          Cmax      maximum melt coefficient (in/hr-deg F or mm/hr-deg C).
          Tbase    snow melt base temperature (deg F or deg C).
          FWF       ratio of free water holding capacity to snow depth (fraction).
          SDO       initial snow depth (in or mm water equivalent).
          FWO       initial free water in pack (in or mm).
          SNNO      fraction of impervious area that can be plowed.
          SD100    snow depth above which there is 100% cover (in or mm water
                     equivalent).
          SDpl ow   depth of snow on plowable areas at which snow removal begins (in or
                     mm).
          Fout      fraction of snow on plowable area transferred out of watershed.
          Fimp      fraction of snow on plowable area transferred to impervious area by
                     plowing.
          Fperv    fraction of snow on plowable area transferred to pervious area by
                     plowing.
          Fimel t   fraction of snow on plowable area converted into immediate melt.
          Fs ub      fraction of snow on plowable area transferred to pervious area in another
                     subcatchment.
          Scatch   name of subcatchment receiving the Fsubcatch fraction of transferred
                     snow.

          Use one set of PLOWABLE, IMPERVIOUS, and PERVIOUS lines for  each  snow
          pack parameter set created. Snow pack parameter sets are associated with specific
          subcatchments in the [SUBCATCHMENTS] section. Multiple subcatchments can share
          the same set of snow pack parameters.

          The PLOWABLE line contains parameters for the impervious area of a subcatchment
          that is subject to snow removal by plowing but not to areal depletion. This area is the
          fraction SNNO of  the total  impervious area.  The IMPERVIOUS line  contains
          parameter values for the remaining impervious area and the PERVIOUS line does the
          same for the entire  pervious area.  Both of the latter two areas are subject to areal
          depletion.

          The  REMOVAL line  describes  how  snow removed from the plowable area is
          transferred onto other areas.  The various transfer fractions should sum to no more
          than 1.0. If the line is omitted then no snow removal takes place.
                                        245

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Section:    [JUNCTIONS]

Purpose:   Identifies each junction node of the drainage system. Junctions are points in space
           where channels and pipes connect together. For sewer systems they can be either
           connection fittings or manholes.

Format:    Name  Elev   (Ymax   YO   Ysur   Apond)
Remarks:  Name
           Elev
           Ymax
           YO
           Ysur

           Apond
name assigned to junction node.
elevation of junction invert (ft or m).
depth from ground to invert elevation (ft or m) (default is 0).
water depth at start of simulation (ft or m) (default is 0).
maximum additional head above ground elevation that manhole junction
can sustain under surcharge conditions (ft or m) (default is 0).
area subjected to surface ponding once water depth exceeds Ymax (ft2 or
m2) (default is 0).
Section:    [OUTFALLS]

Purpose:   Identifies each outfall node (i.e., final downstream boundary) of the drainage system
           and the corresponding water stage elevation. Only one link can be incident on an
           outfall node.
Formats:   Name   Elev
           Name   Elev
           Name   Elev
           Name   Elev
           Name   Elev
     FREE
     NORMAL
     FIXED
     TIDAL
     TIMESERIES
Gate
Gate
Stage    Gate
Tcurve   Gate
Tseries Gate
Remarks:  Name      name assigned to outfall node.
           El ev      invert elevation (ft or m).
           Stage    elevation of fixed stage outfall (ft or m).
           Tcurve   name of curve in [CURVES] section containing tidal height (i.e., outfall
                     stage) v. hour of day over a complete tidal cycle.
           Tseries  name of time series in [TIMESERIES] section that describes how outfall
                     stage varies with time.
           Gate      YES or NO depending on whether a flap gate is present that prevents
                     reverse flow.
                                        246

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Section:   [DIVIDERS]
Purpose:  Identifies each flow divider node of the drainage system. Flow dividers are junctions
          with exactly two outflow conduits where the total outflow is divided between the two
          in a prescribed manner.

Formats:  Name  Elev DivLink  OVERFLOW  (Ymax  YO  Ysur Apond)
          Name  Elev DivLink  CUTOFF   Qmin  (Ymax  YO  Ysur  Apond)
          Name  Elev DivLink  TABULAR Dcurve  (Ymax  YO Ysur Apond)
          Name  Elev DivLink  WEIR     Qmin Ht  Cd  (Ymax YO Ysur Apond)
Remarks:  Name
          Elev
          DivLink
          Qmin

          Dcurve

          Ht
          Cd
          Ymax
          YO
          Ysur

          Apond
          name assigned to divider node.
          invert elevation (ft or m).
          name of link to which flow is diverted.
          flow at which diversion begins for either a CUTOFF or WEIR divider
          (flow units).
          name of curve for TABULAR divider that relates diverted flow to total
          flow.
          height of WEIR divider (ft or m).
          discharge coefficient for WEIR divider.
          depth from ground to invert elevation (ft or m) (default is 0).
          water depth at start of simulation (ft or m) (default is 0).
          maximum additional head above ground elevation that node can sustain
          under surcharge conditions (ft or m) (default is 0).
          area subjected to surface ponding once water depth exceeds Ymax (ft2 or
          m2) (default is 0).
Section:   [STORAGE]
Purpose:
Formats:
Name El
Name El

Remarks:
Identifies each storage node of the drainage system. Storage nodes can have any
shape as specified by a surface area versus water depth relation.
Ymax YO  TABULAR Acurve  (Apond  Fevap SH EC  IMD)
Ymax YO  FUNCTIONAL  Al A2 AO  (Apond  Fevap SH HC  IMD)

Name     name assigned to storage node.
El ev     invert elevation (ft or m).
Ymax     maximum water depth possible (ft or m).
YO        water depth at start of simulation (ft or m).
Acurve   name of curve in [CURVES] section with surface area (ft2 or m2) as a
          function of depth (ft or m) for TABULAR geometry.
Al        coefficient of FUNCTIONAL relation between surface area and depth.
A2        exponenet of FUNCTIONAL relation between surface area and depth.
AO        constant of FUNCTIONAL relation between surface area and depth.
Apond    surface area subjected to ponding once water depth exceeds Ymax (ft2 or
          m2) (default is 0).
                                        247

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           Fevap     fraction of potential evaporation from surface realized (default is 0).

           The following Green-Ampt infiltration parameters are only used when the storage
           node is intended to act as an infiltration basin:
           SH        Soil capillary suction head (in or mm).
           HC        Soil saturated hydraulic conductivity (in/hr or mm/hr).
           IMD       Initial soil moisture deficit (volume of voids / total volume).

           Al, A2,  and AO are used in the following expression that relates surface area (ft2 or
           m2) to water depth (ft or m) for a storage unit with FUNCTIONAL geometry:

               Area  =  AO + Al x DepthAZ
Section:    [CONDUITS]

Purpose:   Identifies each conduit link of the drainage system. Conduits are pipes or channels
           that convey water from one node to another.

Format:    Name   Nodel   Node2   Length   N   Zl   Z2    (QO)

Remarks:  Name     name assigned to conduit link.
           Nodel    name of upstream node.
           Node2    name of downstream node.
           Length  conduit length (ft or m).
           N         value of n (i.e., roughness parameter) in Manning's equation.
           Zl        offset of upstream end of conduit invert above the invert elevation of its
                     upstream node (ft or m).
           Z2        offset of downstream end of conduit invert above the invert elevation of
                     its downstream node (ft or m).
           QO        flow in conduit at start of simulation (flow units) (default is 0).
           The figure below illustrates the meaning of the Zl and Z2 parameters.
           These offsets are expressed as a relative distance above the node invert if the
           LINK_OFFSETS option is set to DEPTH (the default) or as an absolute elevation if it
           is set to ELEVATION.
                                          248

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Section:   [PUMPS]

Purpose:  Identifies each pump link of the drainage system.

Format:   Name   Nodel   Node2   Pcurve    (Status  Startup   Shutoff)
Remarks: Name
          Nodel
          Node2
          Pcurve
          Status
          Startup
          Shutoff
name assigned to pump link.
name of node on inlet side of pump.
name of node on outlet side of pump.
name of pump curve listed in the [CURVES] section of the input.
status at start of simulation (either ON or OFF; default is ON).
depth at inlet node when pump turns on (ft or m) (default is 0).
depth at inlet node when pump shuts off (ft or m) (default is 0).
          See Section 3.2 for a description of the different types of pumps available.
Section:   [ORIFICES]

Purpose:  Identifies each orifice link of the drainage system. An orifice link serves to limit the
          flow exiting a node and is often used to model flow diversions.

Format:  Name   Nodel   Node2   Type   Offset   Cd   (Flap   Orate)

Remarks: Name      name assigned to orifice link.
          Nodel     name of node on inlet end of orifice.
          Node2     name of node on outlet end of orifice.
          Type      orientation of orifice: either SIDE or BOTTOM.
          Offset   amount that a Side Orifice's bottom or the position of a Bottom Orifice is
                     offset above the invert of inlet node (ft or m, expressed as either a depth
                     or as an elevation, depending on the LINK_OFFSETS option setting).
          Cd        discharge coefficient (unitless).
          Flap      YES if flap gate present to prevent reverse flow, NO if not (default is NO).
          Or a t e     time in decimal hours to open a fully closed orifice (or close a fully open
                     one). Use 0 if the orifice can open/close instantaneously.

          The  geometry of an orifice's opening must be described in  the [XSECTIONS]
          section.  The  only allowable shapes are CIRCULAR and RECT_CLOSED (closed
          rectangular).
                Regulator
                Structure
                                                   Orifice
                                                   Offset
                                        249

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Section:   [WEIRS]
Purpose:   Identifies each weir link of the drainage system. Weirs are  used to model flow
          diversions.

Format:   Name   Nodel   Node2   Type   Offset  Cd   (Flap   EC   Cd2)

Remarks:  Name     name assigned to weir link.
          Nodel    name of node on inlet side of wier.
          Node2    name of node on outlet side of weir.
          Type     TRANSVERSE,  SIDEFLOW, V-NOTCH, or TRAPEZOIDAL.
          Offs e t   amount that the weir's crest is offset above the invert of inlet node (ft or
                    m, expressed as either a depth or as an elevation, depending on the
                    LINK_OFFSETS option setting).
          Cd        weir discharge coefficient (for CFS if using US flow units or CMS if
                    using metric flow units).
          Fl ap     YE S if flap gate present to prevent reverse flow, NO if not (default is NO).
          EC        number of end contractions for TRANSVERSE or TRAPEZOIDAL weir
                    (default is 0).
          Cd2       discharge coefficient for triangular ends of a TRAPEZOIDAL weir (for
                    CFS if using US flow units or CMS if using metric flow units) (default is
                    value of Cd).

          The geometry of a weir's opening is described in the  [XSECTIONS] section.  The
          following shapes must be used with each type of weir:
Weir Type
Transverse
Sideflow
V-Notch
Trapezoidal
Cross- Section Shape
RECT OPEN
RECT OPEN
TRIANGULAR
TRAPEZOIDAL
Section:   [OUTLETS]

Purpose:   Identifies each outlet flow control device of the drainage system. These devices are
          used to model outflows from storage units or flow diversions that have a user-defined
          relation between flow rate and water depth.

Format:   Name Nodel Node2 Offset TABULAR/DEPTH Qcurve  (Flap)
          Name Nodel Node2 Offset TABULAR/HEAD  Qcurve  (Flap)
          Name Nodel Node2 Offset FUNCTIONAL/DEPTH  Cl  C2  (Flap)
          Name Nodel Node2 Offset FUNCTIONAL/HEAD   Cl  C2  (Flap)

Remarks:  Name     name assigned to outlet link.
          Node 1    name of node on inlet end of link.
          Node2    name of node on outflow end of link.
                                      250

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           Offs e t   amount that the outlet is offset above the invert of inlet node (ft or m,
                     expressed as either a depth or as an elevation, depending on the
                     LINK_OFFSETS option setting).
           Qcurve   name of the rating curve listed in the [CURVES] section that describes
                     outflow rate (flow units) as a function of:
                     •   water depth above the offset elevation at the inlet node (ft or m) for a
                         TABULAR/DEPTH outlet
                     •   head difference (ft or m) between the inlet and outflow nodes for a
                         TABULAR/HE AD outlet.
           Cl,
           C2        coefficient and exponent, respectively, of a power function that relates
                     outflow (Q) to:
                     •   water depth (ft or m) above the offset elevation at the inlet node for a
                         FUNCTIONAL/DEPTH outlet
                     •   head difference (ft or m) between the inlet and outflow nodes for a
                         FUNCTIONAL/HEAD outlet.
                     (i.e., Q = Cl(H)02 where H is either depth or head).
           Fl ap     YE S if flap gate present to prevent reverse flow, NO if not (default is NO).
Section:    [XSECTIONS]

Purpose:   Provides cross-section geometric data for conduit and regulator links of the drainage
           system.

Formats:   Link  Shape  Geoml  Geom2 Geom3 Geom4   ( Barrels  Culvert )
           Link  CUSTOM      Geoml  Curve  ( Barrels  )
           Link  IRREGULAR   Tsect

Remarks:  Link     name of the conduit, orifice, or weir.
           Shape    cross-section shape (see Tables D-l below or 3-1 for available shapes).
           Geoml    full height of the cross-section (ft or m).
           Geom2-4 auxiliary parameters (width, side slopes, etc.) as listed in Table D-l.
           Barrels number of barrels (i.e., number of parallel pipes of equal size, slope, and
                     roughness) associated with a conduit (default is  1).
           Culvert code number from Table A. 10 for the conduit's inlet geometry if it is a
                     culvert subject to possible inlet flow control (leave blank otherwise).
           Curve    name of a Shape Curve in the [CURVES]  section that defines how width
                     varies with depth.
           Tsect    name of an entry in the [TRANSECTS] section that describes the cross-
                     section geometry of an irregular channel.

           The Culvert code number  is used only for conduits that act as culverts and should be
           analyzed for inlet control conditions using the FHWA HEC-5 method.

           The CUSTOM shape is a closed conduit whose width versus height is described by a
           user-supplied Shape Curve.
                                         251

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    An IRREGULAR cross-section is used to model an open channel whose geometry is
    described by a Transect object.


Table D-l.  Geometric parameters of conduit cross sections.
Shape Geoml Geom2 Geom3 Geom4
CIRCULAR
FORCE MAIN
FILLED_CIRCULAR2
RECT CLOSED
RECT OPEN
TRAPEZOIDAL
TRIANGULAR
HORIZ ELLIPSE
VERT ELLIPSE
ARCH (standard)
ARCH (non-standard)
PARABOLIC
POWER
RECT_TRIANGULAR
RECT_ROUND
MODBASKETHANDLE
EGG
HORSESHOE
GOTHIC
CATENARY
SEMIELLIPTICAL
BASKETHANDLE
SEMICIRCULAR
Diameter
Diameter
Diameter
Full Height
Full Height
Full Height
Full Height
Full Height
Full Height
Size Code4
Full Height
Full Height
Full Height
Full Height
Full Height
Full Height
Full Height
Full Height
Full Height
Full Height
Full Height
Full Height
Full Height

Roughness1
Sediment
Depth
Top Width
Top Width
Base Width
Top Width
Max. Width3
Max. Width3

Max. Width
Top Width
Top Width
Top Width
Top Width
Base Width












Left Slope






Exponent
Triangle
Height
Bottom
Radius
Top Radius5












Right Slope

















'C-factors are used when H-W is the FORCE_MAIN_EQUATION choice in the
[OPTIONS] section while roughness heights (in inches or mm) are used for D-W.
2A circular conduit partially filled with sediment to a specified depth.
3Set to zero to use a standard shaped elliptical pipe as cataloged in the publications
mentioned in the footnote below.
4As listed in either the "Concrete Pipe Design Manual" published by the American
Concrete Pipe Association or "Modern Sewer Design" published by the American Iron
and Steel Institute.
5Set to zero to use a standard modified baskethandle shape whose top radius is half the
base width.
                                  252

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Section:    [LOSSES]

Purpose:   Specifies minor head loss coefficients and flap gates for conduits.

Formats:   Conduit   Ken try  Kexit   Kavg   (Flap)

Remarks:  Conduit  name of conduit.
           Ken try   entrance minor head loss coefficient.
           Kexi t    exit minor head loss coefficient.
           Ka vg     average minor head loss coefficient across length of conduit.
           Fl ap      YES if conduit has a flap valve that prevents back flow, NO otherwise.
                     (Default is NO).

           Minor losses are only computed for the Dynamic Wave flow routing option (see
           [OPTIONS] section). They are computed as Kv2/2g where K = minor loss coefficient,
           v  = velocity,  and  g = acceleration  of  gravity. Entrance losses are  based  on the
           velocity at the entrance of the conduit, exit losses on the exit velocity, and average
           losses on the average velocity.

           Only enter data for conduits that actually  have minor losses or flap valves.
Section:    [TRANSECTS]

Purpose:   Describes the cross-section geometry of natural channels or conduits with irregular
           shapes following the HEC-2 data format.

Formats:   NC   Nleft Nright   Nchanl
           XI   Name  Nsta  Xleft  Xright  000  Lfactor Wfactor Eoffset
           GR   Elev  Station   ...   Elev  Station

Remarks:  Nleft    Manning's n of right overbank portion of channel (use 0 if no change
                     from previous NC line).
           Nri gh t   Manning's n of right overbank portion of channel (use 0 if no change
                     from previous NC line.
           Nchanl   Manning's n of main channel portion of channel (use 0 if no change from
                     previous NC line.
           Name     name assigned to transect.
           Nsta     number of stations across cross-section at which elevation data is
                     supplied.
           Xleft    station position which ends the left overbank portion of the channel (ft or
                     m).
           Xri gh t   station position which begins the right overbank portion of the channel
                     (ft or m).
           Lfactor meander modifier that represents the ratio of the length of a meandering
                     main channel to the length of the overbank area that surrounds it (use 0 if
                     not applicable).
                                         253

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Wfac tor  factor by which distances between stations should be multiplied to
           increase (or decrease) the width of the channel (enter 0 if not applicable).
Eoffset  amount added (or subtracted) from the elevation of each station (ft or m).
El ev      elevation of the channel bottom at a cross-section station relative to some
           fixed reference (ft or m).
Station  distance of a cross-section station from some fixed reference (ft or m).

Transect geometry is described as  shown below, assuming that one is looking in a
downstream direction:
      Left
    Oveibank
Right
• • .• il-.ihl
         Xleft
                     St.ition
                                    Xl Kill)
The first line in this section must always be a NC line. After that, the NC line is only
needed when a transect has different Manning's n values than the previous one.

The Manning's n values on the NC  line will supersede any roughness value entered
for the conduit which uses the irregular cross-section.

There should be one XI line for each transect. Any number of GR lines may follow,
and each GR line can have any number of Elevation-Station data pairs. (In HEC-2 the
GR line is limited to 5 stations.)

The station that defines the left overbank boundary on the XI line must correspond to
one of the station entries on the GR lines that follow. The same holds true for the right
overbank boundary. If there  is no match, a warning will be issued and the program
will assume that no overbank area exists.

The meander modifier is applied to all conduits that use  this  particular transect for
their cross section. It assumes that the length supplied for these conduits is that  of the
longer main channel. SWMM will use the shorter overbank length in its calculations
while increasing the main channel roughness to account for its longer length.
                                254

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Section:   [CONTROLS]

Purpose:   Determines how pumps and regulators will be adjusted based on simulation time or
          conditions at specific nodes and links.

Formats:   Each control rule is a series of statements of the form:
          RULE  rule ID
          IF     condition_l
          AND   condition_2
          OR     condition_3
          AND   condition_4
          Etc.
          THEN  action_l
          AND   action_2
          Etc.
          ELSE  action_3
          AND   action_4
          Etc.
          PRIORITY value

Remarks:  Rule ID         an ID label assigned to the rule.
          condition_n   a condition clause.
          a c ti on_n       an action clause.
          value          a priority value (e.g., a number from 1 to 5).

          A condition clause of a Control Rule has the following format:

          Object  Name   Attribute  Relation   Value

          where Obj ect is a category of object, Name is the object's  assigned ID name,
          Attribute is the name of an attribute or property of the object, Relation is a
          relational operator (=, o, <, <=, >, >=), and Value is an attribute value.

          Some examples of condition clauses are:
              NODE   N23  DEPTH  >  10
              PUMP   P45  STATUS =  OFF
              SIMULATION TIME  =  12:45:00

          The objects and attributes that can appear in a condition clause are as follows:
                                       255

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Object Attributes Value
NODE
LINK
PUMP
ORIFICE
WEIR
SIMULATION
SIMULATION
DEPTH
HEAD
INFLOW
FLOW
DEPTH
STATUS
FLOW
SETTING
SETTING
TIME
DATE
CLOCKTIME
numerical value
numerical value
numerical value
numerical value
numerical value
ON or OFF
numerical value
fraction open
fraction open
elapsed time in
decimal hours or
hr:min:sec
month-day-year
time of day in
hr:min:sec
An action clause of a Control Rule can have one of the following formats:

PUMP  id  STATUS =  ON/OFF
PUMP/ORIFICE/WEIR/OUTLET id SETTING  =  value

where the meaning of SETTING depends on the object being controlled:
   for Pumps it is a multiplier applied to the flow computed from the pump curve,
•  for Orifices it is the fractional amount that the orifice is fully open,
   for Weirs it is the fractional amount of the original freeboard that exists (i.e., weir
   control is accomplished by moving  the crest height up or down),
•  for Outlets it is a multiplier applied to the flow computed from the outlet's rating
   curve.

Modulated controls are control rules that provide for a continuous degree of control
applied to a pump or flow regulator as determined by the value of some  controller
variable,  such as water depth at a node, or by time. The functional relation between
the control setting and the controller variable is specified by using a control curve, a
time  series, or a PID controller. To model these types of controls, the value entry
on the right-hand side of the  action  clause is replaced by  the keyword CURVE,
TIMESERIES, or PID and followed by the id name of the respective control curve
or time series or by the gain, integral time (in minutes), and derivative time  (in
minutes)  of a PID controller. For direct action control the gain is a positive number
while for reverse action control it must be a negative  number. By convention,  the
controller variable used in a control curve or PID control will always be the object
and attribute named in the last condition clause of the rule. The value specified  for
this clause will be the setpoint used in a PID controller.

Some examples of action clauses are:
   PUMP  P67  STATUS  =  OFF
   ORIFICE  0212  SETTING =0.5
   WEIR  W25  SETTING =  CURVE C25
   ORIFICE  ORI  23  SETTING = PID 0.1  0.1  0.0
                               256

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

           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.

Examples:     ; Simple time-based pump control

              RULE  Rl
              IF  SIMULATION  TIME > 8
              THEN  PUMP  12  STATUS  = ON
              ELSE  PUMP  12  STATUS  = OFF

              ; Multi-condition orifice gate control

              RULE  R2A
              IF  NODE 23 DEPTH > 12
              AND LINK  165  FLOW >  100
              THEN  ORIFICE  R55 SETTING  =0.5

              RULE  R2B
              IF  NODE 23 DEPTH > 12
              AND LINK  165  FLOW >  200
              THEN  ORIFICE  R55 SETTING  =1.0

              RULE  R2C
              IF  NODE 23 DEPTH <=  12
              OR  LINK 165  FLOW <=  100
              THEN  ORIFICE  R55 SETTING  = 0

              ; PID control rule

              RULE  PID_1
              IF  NODE 23 DEPTH <>  12
              THEN  ORIFICE  R55 SETTING  = PID  0.5  0.1 0.0
              ; Pump station operation
                                         257

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              RULE  R3A
              IF NODE  Nl  DEPTH  > 5
              THEN  PUMP N1A  STATUS  = ON

              RULE  R3B
              IF NODE  Nl  DEPTH  > 7
              THEN  PUMP NIB  STATUS  = ON

              RULE  R3C
              IF NODE  Nl  DEPTH  <=  3
              THEN  PUMP N1A  STATUS  = OFF
              AND  PUMP NIB STATUS  = OFF
Section:    [POLLUTANTS]

Purpose:   Identifies the pollutants being analyzed.

Format:    Name  Units Grain  Cgw Cii  Kd  (Sflag  CoPoll  CoFract Cdwf)

Remarks:  Name     name assigned to pollutant.
           Uni ts    concentration units (MG/L for milligrams per liter, UG/L for micrograms
                     per liter, or #/L for direct count per liter).
           Grain    concentration of pollutant in rainfall (concentration units).
           Cgw      concentration of pollutant in groundwater (concentration units).
           Cii       concentration of pollutant in inflow/infiltration (concentration units).
           Kdecay  first-order decay coefficient (I/days).
           Sflag   YES if pollutant buildup occurs only when there is snow cover, NO
                     otherwise (default is NO).
           CoPoll  name of co-pollutant (default is no co-pollutant).
           CoFra c t fraction of co-pollutant concentration (default is 0).
           Cdwf     concentration of pollutant in dry weather flow (concentration units).

           FLOW is a reserved word and cannot be used to name a pollutant.

           If pollutant buildup is not restricted to times of snowfall and there is no co-pollutant,
           then the last three parameters can be omitted.

           When pollutant X has a co-pollutant Y,  it means that fraction CoFract of pollutant
           Y's runoff concentration is added to pollutant X's runoff concentration when wash
           off from a subcatchment is computed.

           The dry weather  flow concentration can be overriden for any specific node of the
           conveyance system by editing the node's Inflows property.
                                         258

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Section:   [LANDUSE S]

Purpose:  Identifies the various  categories of  land uses within the  drainage area.  Each
          subcatchment area can be assigned a different mix of land uses. Each land use can be
          subjected to a different street sweeping schedule.

Format:   Name    (Sweep Interval   Availability   LastSweep)

Remarks:  Name            land use name.
          Sweeplnterval days between street sweeping.
          Availability  fraction of pollutant buildup available for removal by street
                           sweeping.
          LastSweep      days since last sweeping at start of the simulation.
Section:   [COVERAGES]

Purpose:  Specifies the percentage of a subcatchment's area that is covered by each category of
          land use.

Format:   Subcat   Landuse   Percent   Landuse   Percent

Remarks: Subcat   subcatchment name.
          Landuse land use name.
          Percen t percent of subcatchment area.

          More than one pair of land use - percentage values can be entered per line. If more
          than one line is needed, then the subcatchment name must still be entered first on the
          succeeding lines.

          If a land use does not pertain to a subcatchment, then it does not have to be entered.

          If no land uses are associated with a subcatchment then no contaminants will appear
          in the runoff from the subcatchment.
Section:   [BUILDUP]

Purpose:  Specifies the rate at which pollutants build up over different land uses between rain
          events.

Format:   Landuse   Pollutant  FuncType   Cl   C2   C3   PerUnit

Remarks:  Landuse     land use name.
          Pollutant  pollutant name.
          FuncType    buildup function type: ( POW /  EXP  / SAT /  EXT).
          Cl ,C2, C3    buildup function parameters (see Table D-2).
                                        259

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           PerUnit
AREA if buildup is per unit area, CURBLENGTH if per length of curb.
           Buildup is measured in pounds (kilograms) per unit of area (or curb length) for
           pollutants whose concentration units are either mg/L or ug/L.  If the  concentration
           units are counts/L, then the buildup is expressed as counts per unit of area (or curb
           length).

           Table D-2. Available pollutant buildup functions (t is antecedent dry days).
Name Function Equation
POW
EXP
SAT
EXT
Power
Exponential
Saturation
External
Min(Cl,C2*tC3)
Cl*(l-exp(-C2*t))
Cl*t/(C3+t)
See below
           For the EXT buildup function, Cl is the maximum possible buildup (mass per area or
           curb length), C2 is a scaling factor,  and C3 is the name of a Time Series that contains
           buildup rates (as mass per area or curb length per day) as a function of time.
Section:    [WASHOFF]

Purpose:   Specifies the rate at which pollutants are washed off from different land uses during
           rain events.

Format:    Landuse   Pollutant  FuncType  Cl   C2    SweepEffic  BMPEffic

Remarks:  Landuse      land use name.
           Pollutant   pollutant name.
           FuncType    washoff function type: EXP  / RC  /  EMC.
           Cl,  C2       washoff function coefficients(see Table D-3).
           SweepEffi c  street sweeping removal efficiency (percent).
           BMPEffi c    BMP removal efficiency (percent).
           Table D-3. Pollutant wash off functions.
Name Function Equation Units
EXP
RC
EMC
Exponential
Rating Curve
Event Mean
Concentration
Cl (runoff)02 (buildup)
Cl (runoff)02
Cl
Mass/hour
Mass/sec
Mass/Liter
           Each washoff function expresses its results in different units.
                                         260

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           For the Exponential function the runoff variable is expressed in catchment depth per
           unit of time (inches per hour or millimeters per hour), while for the Rating Curve
           function it is in whatever flow units were specified in the [OPTIONS] section of the
           input file (e.g., CFS, CMS, etc.).  The buildup parameter in the Exponential function
           is the current total buildup over the subcatchment's land use area in mass units. The
           units of Cl in the Exponential function are (in/hr) "C2 per hour (or (mm/hr) "C2 per
           hour). For the Rating  Curve function, the units  of Cl depend on the  flow units
           employed. For the EMC (event  mean concentration)  function, Cl is  always in
           concentration units.
Section:    [TREATMENT]

Purpose:   Specifies the  degree of treatment received by pollutants  at specific nodes of the
           drainage system.
Format:
Node   Pollut   Result = Func
Remarks:  Node     Name of node where treatment occurs.
           Pollut   Name of pollutant receiving treatment.
           Resul t   Result computed by treatment function. Choices are:
                     C - function computes effluent concentration
                     R - function computes fractional removal.
           Fun c     mathematical function expressing treatment result in terms of pollutant
                     concentrations, pollutant removals, and other standard variables (see
                     below).

           Treatment functions can be any well-formed mathematical expression involving:
              inlet pollutant concentrations (use the pollutant name to represent a
              concentration)
           •  removal of other pollutants (use R_ prepended to the pollutant name to represent
              removal)
           •  process variables which include:
              FLOW for flow rate into node (user's flow units)
              DEPTH for water depth above node invert (ft or m)
              AREA for node surface area (ft2 or m2)
              DT for routing time step (seconds)
              HRT for hydraulic residence time (hours)
Examples:  ; 1-st order decay of BOD
           Node23   BOD    C  = BOD
                               exp(-0.05*HRT)
           ; lead removal is 20% of TSS removal
           Node23   Lead   R  = 0.2  * R  TSS
                                         261

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Section:    [DWF]

Purpose:   Specifies dry weather flow and its quality entering the drainage system at specific
           nodes.

Format:    Node  Item   Value   (Patl   Pat2   Pat3   Pat4)

Remarks:  Node     name of node where dry weather flow enters.
           Item     keyword FLOW for flow or pollutant name for quality constituent.
           Val ue    average baseline value for corresponding Item (flow or concentration
                     units).
           Patl,
           Pat 2,
           etc.        names of up to four time patterns appearing in the [PATTERNS] section.

           The actual dry weather input will  equal the product  of the baseline value and any
           adjustment factors supplied by the specified patterns.  (If not supplied, an adjustment
           factor defaults to 1.0.)
Section:    [PATTERNS]

Purpose:   Specifies time pattern of dry weather  flow or quality in the  form of adjustment
           factors applied as multipliers to baseline values.

Format:    Name  MONTHLY     Factor I   Factor 2   . .  .   Factor 12
           Name  DAILY        Factorl   Factor2   . .  .   Factor!
           Name  HOURLY      Factorl   Factor2   . .  .   Factor24
           Name  WEEKEND     Factorl   Factor2   . .  .   Factor24

Remarks:  Name     name used to identify the pattern.
           Factorl,
           Factor 2,
           etc.        multiplier values.

           The MONTHLY format is used to set monthly  pattern factors for dry weather flow
           constituents.

           The DAILY format is used to set dry weather pattern factors  for each day of the
           week, where Sunday is day 1.

           The HOURLY format is used to set dry weather factors for each hour of the of the day
           starting from midnight. If these  factors are different for weekend days  than for
           weekday days then the WEEKEND format can be used to specify hourly adjustment
           factors just for weekends.

           More than one line can be used to enter a pattern's factors by repeating the  pattern's
           name (but not the pattern type) at the beginning of each additional line.
                                         262

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          The pattern factors are applied as multipliers to any baseline dry weather flows or
          quality concentrations supplied in the [DWF] section.
Examples: ;  Day of week adjustment  factors
          Dl   DAILY   0.5   1.0   1.0   1.0   1.0
          D2   DAILY   0.8   0.9   1.0   1.1   1.0

          ;  Hourly adjustment  factors
          HI  HOURLY   0.5  0.6 0.7 0.8  0.8  0.9
          HI            1.11.21.31.51.11.0
          HI            0.90.80.70.60.50.5
          HI            0.50.50.50.50.50.5
                            1.0
                            0.9
0.5
0.8
Section:   [INFLOWS]

Purpose:   Specifies external hydrographs and pollutographs that enter the drainage system at
          specific nodes.

Formats:   Node FLOW    Fseries  ('FLOW     1.0       Sfactor Base Pat)
          Node Pollut  Pseries  (Format  (Mfactor Sfactor Base Pat)
Remarks:  Node
          Fseries

          Pollut
          Pseries

          Format

          Mfactor
          Sfactor

          Base

          Pat
name of node where external inflow enters.
name of time series in [TIMESERIES] section describing how
external inflows vary with time.
name of pollutant.
name of time series describing how external pollutant loading
varies with time.
CONCEN if pollutant inflow is described as a concentration,
MASS if it is described as a mass flow rate (default is CONCEN).
the factor that converts the inflow's mass flow rate units into the
project's mass units per second, where the project's mass units
are those specified for the pollutant in the [POLLUTANTS]
section (default is 1.0 - see example below).
scaling factor that multiplies the recorded time series values
(default is 1.0).
constant baseline value added to the time series value (default is
0.0).
name of optional time pattern in [PATTERNS] section used to
adjust the baseline value on a periodic basis.
          External inflows are represented by both a constant and time varying component as
          follows:
              Inflow =  (Baseline  value) * (Pattern factor)  +
                        (Scaling  factor) * (Time  series value)
                                       263

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          If an external inflow of a pollutant concentration is specified for a node, then there
          must also be an external inflow of FLOW provided for the same node, unless the node
          is an Outfall. In that case a pollutant can enter the system during periods when the
          outfall is submerged and reverse flow occurs.
Examples: NODE2
          NODE33
FLOW  N2FLOW
TSS    N33TSS  CONCEN
          ;Mass  inflow of  BOD  in  time  series N65BOD given  in Ibs/hr
          ;(126  converts  Ibs/hr to mg/sec)
          NODE65   BOD  N65BOD   MASS   126

          ;Flow  inflow with baseline  and  scaling factor
          N176   FLOW   FLOW 176  FLOW   1.0   0.5   12.7   FlowPat
Section:   [LOADINGS]

Purpose:   Specifies the pollutant buildup that exists on each subcatchment at the start of a
          simulation.

Format:   Subcat  Pollut   InitBuildup   Pollut   InitBuildup  ...

Remarks:  Subcat         name of a subcatchment.
          Pollut         name of a pollutant.
          Ini tBuildup   initial buildup of pollutant (Ibs/acre or kg/hectare).

          More than one pair of pollutant - buildup values can be entered per line. If more than
          one line is needed, then the subcatchment name must still be entered first on the
          succeeding lines.

          If an  initial  buildup is  not specified for a pollutant, then its initial buildup is
          computed by applying the DRY_DAYS option (specified in the [OPTIONS]  section)
          to the pollutant's buildup function for each land use in the subcatchment.
Section:   [RDII]

Purpose:   Specifies the parameters that describe rainfall-dependent infiltration/inflow (RDII)
          entering the drainage system at specific nodes.

Format:   Node   UHgroup   SewerArea

Remarks:  Node         name of a node.
          UHgroup      name of an RDII unit hydrograph group specified in the
                        [HYDROGRAPHS] section.
          SewerArea   area of the sewershed which contributes RDII to the node (acres or
                        hectares).
                                       264

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Section:    [HYDROGRAPHS]
Purpose:   Specifies the shapes of the triangular unit hydrographs that determine the amount of
           rainfall-dependent infiltration/inflow (RDII) entering the drainage system.

Formats:   Name   Raingage
           Name   Month   SHORT/MEDIUM/LONG  R   T   K  (Dmax Dree  DO)
Remarks:  Name
           Raingage
           Month
           R
           T
           K
           Dmax
           Dree
           DO
name assigned to a unit hydrograph group.
name of the rain gage used by the unit hydrograph group.
month of the year (e.g., JAN, FEE, etc. or ALL for all months).
response ratio for the unit hydrograph.
time to peak (hours) for the unit hydrograph.
recession limb ratio for the unit hydrograph.
maximum initial  abstraction depth available (in rain depth units).
initial abstraction recovery rate (in rain depth units per day)
initial abstraction depth already filled at the start of the simulation (in
rain depth units).
           For each group of unit hydrographs, use one line to specify its rain gage followed by
           as many lines as are needed to define  each unit hydrograph  used by the group
           throughout the year. Three separate unit hydrographs, that represent the short-term,
           medium-term, and long-term RDII responses, can be  defined for each month (or all
           months taken together). Months not listed are assumed to have no RDII.

           The response ratio (R) is the fraction of a unit of rainfall depth  that becomes RDII.
           The sum of the ratios for a set of three hydrographs does not have to equal 1.0.

           The recession limb ratio (K) is the ratio of the duration of the hydrograph's recession
           limb to  the time to  peak (T) making the hydrograph time base equal to T*(1+K)
           hours. The area under each unit hydrograph is  1 inch (or mm).

           The optional initial abstraction parameters determine how much rainfall is lost at the
           start of a storm to interception and depression storage.  If not supplied then the default
           is no initial abstraction.

Examples: ; All three unit hydrographs in this group have the same shapes except those in July,
           ; which have only a short- and medium-term response with different shapes than
           ; those for the other months of the year
           UH101   RG1
           UH101   ALL  SHORT   0.033
           UH101   ALL  MEDIUM  0.300
           UH101   ALL  LONG    0.033
           UH101   JUL  SHORT   0.033
           UH101
          0.011
1.0
3.0
10.0
0.5
2 .0
2.0
                                          265

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Section:   [CURVES]

Purpose:  Describes a relationship between two variables in tabular format.

Format:   Name   Type  X-value   Y-value   . . .

Remarks:  Name     name assigned to table
          Type     STORAGE  / SHAPE  /  DIVERSION  / TIDAL  / PUMP1  /
                    PUMP2  /  PUMPS /  PUMP4 /  RATING /  CONTROL
          X-value an x (independent variable) value
          Y-value the y (dependent variable) value corresponding to x

          Multiple pairs of x-y values can appear on a line. If more than one line is needed,
          repeat the curve's name (but not the type) on subsequent lines. The x-values must be
          entered in increasing order.

          Choices for curve  type  have  the following meanings (flows are expressed in the
          user's choice of flow units set in the [OPTIONS] section):

              STORAGE      (surface area in ft2 (m2) v. depth in ft (m) for a storage unit node)

              SHAPE        (width v. depth for a custom closed cross-section, both
                            normalized with respect to full depth)
              DIVERSION   (diverted outflow v. total inflow for a flow divider node)

              TIDAL        (water surface elevation in ft (m) v. hour of the day for an outfall
                            node)
              PUMP1        (pump outflow v. increment of inlet node volume in ft3 (m3))

              PUMP2        (pump outflow v. increment of inlet node depth in ft (m))

              PUMPS        (pump outflow v. head difference between outlet and inlet nodes
                            in ft (m))

              PUMP4        (pump outflow v. continuous depth in ft (m))

              RATING       (outlet flow v. head in ft (m))

              CONTROL     (control setting v. controller variable)

          See Section 3.2 for illustrations of the different types of pump curves.

Examples: ; Storage  curve (x = depth,  y  =  surface  area)
          AC1   STORAGE   0   1000  2   2000    4   3500   6   4200   8   5000

          ;Typel  pump curve (x  = inlet  wet  well  volume,  y  =  flow )
          PCI   PUMP1
          PCI   100   5  300   10   500   20
                                        266

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Section:   [TIMESERIES]

Purpose:  Describes how a quantity varies over time.

Formats:  Name   ( Date  )   Hour   Value
          Name   Time   Value   . . .
          Name   FILE   Fname
Remarks:  Name
          Date

          Hour
           Time

           Value
           Fname
name assigned to time series.
date in Month/Day/Year format (e.g., June 15, 2001 would be
6/15/2001).
24-hour military time (e.g., 8:40 pm would be 20:40) relative to the last
date specified (or to midnight of the starting date of the simulation if no
previous date was specified).
hours since the start of the simulation, expressed as a decimal number or
as hours:minutes.
value corresponding to given date and time.
name of a file in which the time series data are stored
          There are two options for supplying the data for a time series:
          i. directly within this input file section as described by the first two formats
          ii. through an external data file named with the third format.

          When direct data entry is used, multiple date-time-value or time-value entries can
          appear on a line. If more than one line is needed, the table's name must be repeated as
          the first entry on subsequent lines.

          When an external file is used, each line in the file must use the same formats listed
          above, except that only one date-time-value (or time-value) entry is allowed per line.
          Any line that begins with a  semicolon is considered a comment line and is ignored.
          Blank lines are not allowed.

          Note that there are  two methods for describing the occurrence time of time  series
          data:
              as calendar date/time of day (which requires that at least one date, at the start of
              the series, be entered)
              as elapsed hours since the start of the simulation.
          For the first method, dates need only be entered at points in time when a new day
          occurs.

Examples: ; Rainfall time series  with dates  specified
          TS1  6-15-2001  7:00  0.1 8:00 0.2 9:00  0.05 10:00 0
          TS1  6-21-2001  4:00  0.2 5:00 0  14:00  0.1 15:00  0

          ;Inflow  hydrograph  - time  relative to start  of  simulation
          ; (hours  can be expressed  as decimal  hours or  hr:min)
          HY1   0    0 1.25 100  2:30 150 3.0 120  4.5 0
          HY1   32:10  0 34.0  57 35.33 85  48.67  24  50 0
                                        267

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Section:
           [LID  CONTROLS]
Purpose:  Defines scale-independent LID controls that can be deployed within subcatchments.

Formats:  Name  Type

          One or more of the following lines depending on Type:

          Name  SURFACE   StorHt   VegFrac  Rough   Slope   Xslope
          Name  SOIL       Thick   For   FC   WP  Ksat   Kcoeff   Suet
          Name  PAVEMENT  Thick   Vratio   Fraclmp   Perm   Vclog
          Name  STORAGE   Height   Vratio   Filt   Vclog
          Name  DRAIN      Coeff   Expon  Offset  Delay

          Name      Name assigned to LID process.
          Type      BC for bio-retention cell; PP  for porous pavement; IT for infiltration
                     trench; RB for rain barrel; VS for vegetative swale.
Remarks:
          For LIDs with Surface Layers:
          StorHt   When confining walls or berms are present this is the maximum depth to
                     which water can pond above the surface of the unit before overflow
                     occurs (in inches or mm). For LIDs that experience overland flow it is
                     the height of any surface  depression storage. For swales, it is the height
                     of its trapezoidal cross section.
          VegFra c  Fraction of the area above the surface that is filled with vegetation.
          Rough    Manning's n for overland flow over the surface of porous pavement or a
                     vegetative swale. Use 0 for other types of LIDs.
          Slope    Slope of porous pavement surface or vegetative swale (percent). Use  0
                     for other types of LIDs.
          Xslope   Slope (run  over rise) of the side walls of a vegetative swale's cross
                     section. Use 0 for other types of LIDs.

          For LIDs with Pavement Layers:
          Thick    Thickness of the pavement layer (inches or mm).
          Vratio   Void ratio (volume of void space relative to the  volume of solids in the
                     pavement for continuous systems or for the fill material used in modular
                     systems). Note that porosity = void ratio / (1 + void ratio).
          Fraclmp  Ratio of impervious paver material  to total area  for modular systems;  0
                     for continuous porous pavement systems.
          Perm      Permeability of the concrete or asphalt used in continuous systems or
                     hydraulic conductivity of the  fill  material (gravel or sand) used in
                     modular systems (in/hr or mm/hr).
          Vclog    Number of pavement layer void volumes of runoff treated it takes to
                     completely clog the pavement. Use a value of 0 to ignore clogging.

          For LIDs with Soil Layers:
          Thick    Thickness of the soil layer (inches or mm).
          For       Soil porosity (volume of pore space relative to total volume).
                                        268

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FC        Soil field capacity (volume of pore water relative to total volume after
           the soil has been allowed to drain fully).
WP        Soil wilting point (volume of pore water relative to total volume for a
           well dried soil where only bound water remains).
Ksat      Soil's saturated hydraulic conductivity (in/hr or mm/hr).
Kcoeff   Slope of the curve of log(conductivity) versus  soil moisture content
           (dimensionless).
Suet      Soil capillary suction (in or mm).

For LIDs with Storage Layers:
Height   Thickness of the storage layer or height of a rain barrel (inches or mm).
Vra tio   Void ratio (volume of void space relative to the volume of solids in the
           layer). Note that porosity = void ratio / (1 + void ratio).
Filt      The filtration rate of the layer when first constructed (in/hr or mm/hr). If
           there is an impermeable floor or liner below the layer then use a value of
           0.
Vclog    Number of storage layer  void  volumes  of  runoff treated it takes to
           completely  clog the layer. Use a value of 0 to ignore clogging.

        Values for Vra tio, Filt, and Vclog are ignored for rain barrels.

For LIDs with Underdrains:
Coeff    Coefficient C that determines the rate of flow through the underdrain as a
           function of height of stored water above the drain bottom.
Expon    Exponent n that determines the rate of flow through the underdrain as a
           function of height of stored water above the drain outlet.
Offs e t   Height of underdrain piping or outlet above the bottom of the storage
           layer or rain barrel (inches or mm).
Delay    The number of dry weather hours that must elapse before the drain line
           in a rain barrel is opened (the line is assumed to be closed once rainfall
           begins).  This parameter is ignored for other types of LIDs.

The following table shows which layers are required (x) or are optional (o) for each
type of LID process:
LID Type
Bio-Retention Cell
Porous Pavement
Infiltration Trench
Rain Barrel
Vegetative Swale
Surface
X
X
X

X
Pavement

X



Soil
X




Storage
X
X
X
X

Underdrain
o
0
o
X

The equation used to compute flow rate out of the underdrain per unit area of the LID
(in in/hr or mm/hr) is q = C(h — H(j)n where q is outflow, h is height of stored water
(inches or mm) and Hd is the drain offset height.

The actual dimensions of an LID control are provided in the  [LID_USAGE] section
when it is placed in a particular subcatchment.
                               269

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Examples: ;A  street planter  with  no underdrain
          Planter   BC
          Planter   SURFACE    6  0.3   0      0       0
          Planter   SOIL       24  0.5   0.1   0.05   1.2
          Planter   STORAGE   12  0.5   20    0

          ;A  green  roof  with impermeable bottom
          GR1   BC
                   2.4
GR1
GR1
GR1
GR1
SURFACE
SOIL
STORAGE
DRAIN
3
3
3
5
0
0
0
0

.5
.5
.5
0
0
0
0
                                           0
                                           0.05
                                           0
                                           0
       0
       1.2
2.4
          ;A  rain barrel  that drains
          RB12   RB
          RB12   STORAGE   36   0     0
          RB12   DRAIN     10   0.5   0
6 hours  after  rainfall  ends
          ;A  grass  swale  24  in. high with  5:1 side slope
          Swale  VS
          Swale  SURFACE   24   0   0.2   3  5
Section:   [LIDJJSAGE]

Purpose:   Deploys LID controls within specific subcatchment areas.

Format:

   Subcat  LID Number Area Width InitSat  Fromlmp  ToPerv  (RptFile)

Remarks:  Subcat   The name of the subcatchment using the LID process.
          LID       The name of an LID process defined in the [LID_CONTROLS] section.
          Number   The number of replicate LID units deployed.
          Area      The area of each replicate unit (ft2 or m2).
          Width    The width of the outflow face of each identical LID unit (in ft or m). This
                    parameter only applies  to LID processes such as porous pavement and
                    vegetative swales that use overland flow to convey surface runoff off of
                    the unit. (The other LID processes, such as  bio-retention cells and
                    infiltration trenches simply spill any excess captured runoff over their
                    berms.)
          InitSat  The percent to which the unit's soil layer or storage layer is initially filled
                    with water.
          Fromlmp  The percent of the  impervious portion of the subcatchment's non-LID
                    area whose  runoff is treated by the LID units. If the LID unit treats only
                    direct rainfall, such as with a green  roof, then this value should be 0. If
                    the LID takes up the entire subcatchment then this field is ignored.
                                      270

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          ToPerv   1  if the  outflow from the LID is returned onto the subcatchment's
                     pervious area rather than going to the subcatchment's outlet; 0 otherwise.
                     An example of where this might apply is a rain barrel whose contents are
                     used to irrigate a lawn area. This field is ignored if the LID takes up the
                     entire subcatchment.
          RptFile  Optional name of a file to which detailed time series results for the LID
                     will be written. Enclose the name in double quotes if it contains spaces
                     and include the full path if it is different than the  S WMM input file path.

          More than one type of LID process can be deployed within a  subcatchment as long as
          their total area does not exceed that of the  subcatchment and the  total  percent
          impervious area treated does not exceed 100.

Examples: ;34 rain barrels  of  12  sq  ft each are  placed  in
          ;subcatchment  SI.  They are  initially empty  and treat 17%
          ;of the  runoff  from the subcatchment's  impervious  area.
          ;The  outflow from the  barrels  is  returned to  the
          ;subcatchment's pervious area.
          SI   RB14   34   12   0   0   17   1

          ;Subcatchment  S2  consists  entirely  of  a single vegetative
          ;swale 200  ft  long by  50 ft wide.
          S2   Swale   1   10000   50  0   0   0  "swale.rpt"
D3.    Map Data Section

SWMM's graphical user interface (GUI) can display a schematic map of the drainage area being
analyzed. This map displays subcatchments as polygons, nodes as circles, links as polylines, and
rain gages as bitmap symbols. In addition it can display text labels and a backdrop image, such as
a street map. The GUI has tools for drawing, editing, moving, and displaying these map elements.
The map's coordinate  data are stored in the format  described below. Normally these data are
simply appended to the SWMM input file by the GUI so users do not have to concern themselves
with it. However it is sometimes more convenient to import map data from some other source,
such as a CAD or GIS file, rather than drawing a map from scratch using  the GUI. In this case the
data can be added to  the SWMM project file using any text editor or  spreadsheet program.
SWMM does not provide any automated facility for converting coordinate data from other file
formats into the SWMM map data format.

SWMM's map data are organized into the following seven sections:

    [MAP]            X,Y coordinates of the map's bounding rectangle
    [POLYGONS]      X,Y coordinates for each vertex of subcatchment polygons
    [COORDINATES]  X,Y coordinates for nodes
    [VERT ICES]      X,Y coordinates for each interior vertex of polyline links
    [LABELS]        X,Y coordinates and text of labels
    [SYMBOLS]       X,Y coordinates for rain gages
    [BACKDROP]      X,Y coordinates of the bounding rectangle and file name of the backdrop
                    image.
                                       271

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Figure D-2 displays a sample map and Figure D-3 the data that describes it. Note that only one
link, 3, has interior vertices which give it a curved shape. Also observe that this map's coordinate
system has no units, so that the positions of its objects may not necessarily coincide to their real-
world locations.

                           Figure D-2. Example study area map.
                                            272

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          [MAP]
          DIMENSIONS
          UNITS

          [COORDINATES]
          ;;Node
          Nl
          N2
          N3
          N4

          [VERTICES]
          ;;Link
          3
          3

          [SYMBOLS]
          ;;Gage
          Gl

          [Polygons]
          ;;Subcatchment
          SI
          SI
          SI
0.00   0.00
None
   X-Coord
   4006.62
   6953.64
   4635.76
   8509.93
   X-Coord
   5430.46
   7251.66
   X-Coord
   5298 .01
   X-Coord
   3708 .61
   4834.44
   3675.50
              10000.00  10000.00
   Y-Coord
   5463.58
   4768.21
   3443.71
   827.81
   Y-Coord
   2019.87
   927.15
   Y-Coord
   9139.07
   Y-Coord
   8543.05
   7019.87
   4834.44
         < additional  vertices not listed >
          S2                  6523.18          8079.47
          S2                  8112.58          8841.06
          [LABELS]
          ;;X-Coord
          5033.11
          1655.63
          7715.23
Y-Coord
8807.95
7450.33
7549.67
Label
"Gl"
"SI"
" S 2 "
                    Figure D-3. Data for map shown in Figure D-2.
A detailed description of each map data section will now be given. Remember that map data are
only used as a visualization aid for SWMM's GUI  and they play no role in any of the runoff or
routing computations. Map data are not needed for running the command line version of SWMM.
                                        273

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Section:    [MAP]

Purpose:   Provides dimensions and distance units for the map.

Formats:   DIMENSIONS  XI  Yl  X2  Y2
           UNITS     FEET  /  METERS  / DEGREES  /  NONE

Remarks:  XI        lower-left X coordinate of full map extent
           Yl        lower-left Y coordinate of full map extent
           X2        upper-right X coordinate of full map extent
           Y2        upper-right Y coordinate of full map extent
Section:    [COORDINATES]

Purpose:   Assigns X,Y coordinates to drainage system nodes.

Format:    Node  Xcoord   Ycoord

Remarks:  Node     name of node.
           Xcoord   horizontal coordinate relative to origin in lower left of map.
           Ycoord   vertical coordinate relative to origin in lower left of map.
Section:    [VERTICES]

Purpose:   Assigns X,Y coordinates to interior vertex points of curved drainage system links.

Format:    Link  Xcoord   Ycoord

Remarks:  Link     name of link.
           Xcoord   horizontal coordinate of vertex relative to origin in lower left of map.
           Ycoord   vertical coordinate of vertex relative to origin in lower left of map.

           Include a separate line for each interior vertex of the link, ordered from the inlet node
           to the outlet node.

           Straight-line links have no interior vertices and therefore are not listed in this section.
                                         274

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Section:    [POLYGONS]

Purpose:   Assigns X,Y coordinates to vertex points of polygons that define a subcatchment
           boundary.

Format:    Subcat   Xcoord   Ycoord

Remarks:  Subcat   name of subcatchment.
           Xcoord   horizontal coordinate of vertex relative to origin in lower left of map.
           Ycoord   vertical coordinate of vertex relative to origin in lower left of map.

           Include a separate line  for each  vertex of the subcatchment polygon, ordered in a
           consistent clockwise or counter-clockwise sequence.
Section:    [SYMBOLS]

Purpose:   Assigns X,Y coordinates to rain gage symbols.

Format:    Gage   Xcoord   Ycoord

Remarks:  Gage      name of rain gage.
           Xcoord   horizontal coordinate relative to origin in lower left of map.
           Ycoord   vertical coordinate relative to origin in lower left of map.
                                        275

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Section:    [LABELS]

Purpose:   Assigns X,Y coordinates to user-defined map labels.

Format:    Xcoord   Ycoord   Label  (Anchor   Font   Size   Bold   Italic)

Remarks:  Xcoord   horizontal coordinate relative to origin in lower left of map.
           Ycoord   vertical coordinate relative to origin in lower left of map.
           Label    text of label surrounded by double quotes.
           Anchor   name of node or subcatchment that anchors the label on zoom-ins (use an
                     empty pair of double quotes if there is no anchor).
           Fon t      name of label's font (surround by double quotes if the font name includes
                     spaces).
           Si ze      font size in points.
           Bold      YES for bold font, NO otherwise.
           Italic   YES for italic font, NO otherwise.

           Use of the anchor node feature will prevent the  label  from  moving outside the
           viewing area when the map is zoomed in on.

           If no font information is provided then a default font is used to draw the label.
Section:    [BACKDROP]

Purpose:   Specifies file name and coordinates of map's backdrop image.

Formats:   FILE      Fname
           DIMENSIONS XI  Yl  X2  Y2
Remarks:  Fname
           XI
           Yl
           X2
           Y2
name of file containing backdrop image
lower-left X coordinate of backdrop image
lower-left Y coordinate of backdrop image
upper-right X coordinate of backdrop image
upper-right Y coordinate of backdrop image
                                        276

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APPENDIX E - ERROR AND WARNING MESSAGES
ERROR 101:  memory allocation error.
              There is not enough physical memory in the computer to analyze the study area.

ERROR 103:  cannot solve KW equations for Link xxx.
              The  internal solver for Kinematic Wave routing failed to converge for the
              specified link at some stage of the simulation.

ERROR 105:  cannot open ODE solver.
              The system could not open its Ordinary Differential Equation solver.

ERROR 107:  cannot compute a valid time step.
              A valid time step for runoff or flow routing calculations (i.e.,  a number greater
              than 0) could not be computed at some stage of the simulation.

ERROR 108:  ambiguous outlet ID name for Subcatchment xxx.
              The name  of the element identified as the outlet of a subcatchment belongs to
              both a node and a subcatchment in the project's data base.

ERROR 109:  invalid parameter values for Aquifer xxx.
              The properties entered for an aquifer object were either invalid numbers or were
              inconsistent with one another (e.g., the soil field capacity  was higher than the
              porosity).

ERROR 111:  invalid length for Conduit xxx.
              Conduits cannot have zero or negative  lengths.

ERROR 113:  invalid roughness for Conduit xxx.
              Conduits cannot have zero or negative  roughness values.

ERROR 114:  invalid number of barrels for Conduit xxx.
              Conduits must consist of one or more barrels.

ERROR 115:  adverse slope for Conduit xxx.
              Under Steady or Kinematic Wave routing, all conduits must  have positive slopes.
              This can usually be corrected by reversing  the inlet and  outlet nodes  of the
              conduit (i.e., right click on the conduit and select Reverse from the popup menu
              that appears). Adverse slopes are permitted under Dynamic Wave routing.

ERROR 117:  no cross section defined for Link xxx.
              Cross section geometry was never defined for the specified link.

ERROR 119:  invalid cross section for Link xxx.
              Either an invalid shape or invalid set of dimensions was specified for a link's
              cross section.

ERROR 121:  missing or invalid pump curve assigned to Pump xxx.
              Either no pump curve or an invalid type of curve was specified for a pump.
                                         277

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ERROR 131:  the following links form cyclic loops in the drainage system.
              The Steady  and Kinematic Wave flow routing methods cannot be  applied to
              systems where a cyclic loop exists (i.e., a directed path along a set of links that
              begins and ends at the same node). Most often the cyclic nature of the loop can
              be eliminated by reversing the direction of one of its links (i.e.,  switching the
              inlet and outlet nodes of the link). The names of the links that form the loop will
              be listed following this message.

ERROR 133:  Node xxx has more than one outlet link.
              Under Steady and Kinematic Wave flow routing, a junction node can have only a
              single outlet link.

ERROR 134:  Node xxx has more than one DUMMY outlet link.
              Only a single conduit with a  DUMMY cross-section can be directed out of a
              node.

ERROR 135:  Divider xxx does not have two outlet links.
              Flow divider nodes must have two outlet links connected to them.

ERROR 136:  Divider xxx has invalid diversion link.
              The link specified as being the one carrying the diverted flow from a flow divider
              node was defined with a different inlet node.

ERROR 137:  Weir Divider xxx has invalid parameters.
              The parameters of a Weir-type divider node either are non-positive numbers or
              are inconsistent (i.e., the value of the discharge coefficient times the weir height
              raised to the 3/2 power must be greater than the minimum flow parameter).

ERROR 138:  Node xxx has initial depth greater than maximum depth.
              Self-explanatory.

ERROR 139:  Regulator xxx is the outlet of a non-storage node.
              Under Steady or Kinematic Wave flow routing, orifices, weirs, and outlet links
              can only be used as outflow links from storage  nodes.

ERROR 141:  Outfall xxx  has more than 1 inlet link or an outlet link.
              An outfall node is only permitted to have one link attached to it.

ERROR 143:  Regulator xxx has invalid cross-section shape.
              An orifice must have  either a CIRCULAR or RECT_CLOSED shape, while a
              weir  must have either a  RECT_OPEN, TRAPEZOIDAL,  or TRIANGULAR
              shape.

ERROR 145:  Drainage system has no acceptable outlet nodes.
              Under Dynamic Wave flow routing, there must be at least one node designated as
              an outfall.

ERROR 151:  a Unit Hydrograph in set xxx has invalid time base.
              The time base of a Unit Hydrograph cannot be negative and if positive, must not
              be less than the recording interval for its rain gage.
                                         278

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ERROR 153:  a Unit Hydrograph in set xxx has invalid response ratios.
              The response ratios for a set of Unit Hydrographs (the short-, medium-, and long-
              term response hydrographs) must be between 0 and 1.0 and cannot add up to a
              value greater than 1.0

ERROR 155:  invalid sewer area for RDII at Node xxx.
              The sewer area contributing RDII inflow to a node cannot be a negative number.

ERROR 156:  inconsistent data file name for Rain Gage xxx.
              If two Rain Gages use files for their data sources and have the same Station IDs
              then they must also use the  same data files.

ERROR 157:  inconsistent rainfall format for Rain Gage xxx.
              If two or more rain gages  use the same Time Series for their rainfall data then
              they  must  all use  the same data format (intensity, volume,  or  cumulative
              volume).

ERROR 158:  time series for Rain Gage xxx is also  used by another object.
              A rainfall Time Series associated with a Rain Gage cannot be used by another
              object that is not also a Rain Gage.

ERROR 159:  inconsistent time interval  for Rain Gage xxx.
              The recording time interval specified for the rain gage is greater than the smallest
              time interval between values in the Time Series used by the gage.

ERROR 161:  cyclic dependency in treatment functions at Node xxx.
              An example would be where the removal of pollutant 1 is defined as a function
              of the removal of pollutant 2 while the removal of pollutant 2 is defined as a
              function of the removal of pollutant 1.

ERROR 171:  Curve xxx has its data out of sequence.
              The X-values of a curve object must be entered in increasing order.

ERROR 173:  Time Series xxx has its data out of sequence.
              The time (or date/time) values of a time series  must be  entered in sequential
              order.

ERROR 181:  invalid Snow Melt Climatology parameters.
              The ATI Weight or Negative Melt Ratio parameters are not between 0 and 1 or
              the site latitude is not between -60 and  +60 degrees.

ERROR 182:  invalid parameters for Snow Pack xxx.
              A snow pack's  minimum  melt coefficient is greater than  its maximum
              coefficient; the fractions of free water capacity or impervious plowable area are
              not between 0 and 1; or the snow removal fractions sum to more than 1.0.

ERROR 183:  no type specified for LID xxx.
              A named LID control has layers defined for it but its LID type was never
              specified.
                                         279

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ERROR 184:  missing layer for LID xxx.
              A required design layer is missing for the specified LID control.

ERROR 185:  invalid parameter value for LID xxx.
              An invalid value was supplied for an LID control's design parameter.

ERROR 187:  LID area exceeds total area for Subcatchment xxx.
              The area of the LID controls placed within the subcatchment is greater than that
              of the subcatchment itself.

ERROR 191:  simulation start date comes after ending date.
              Self-explanatory.

ERROR 193:  report start date  comes after ending date.
              Self-explanatory.

ERROR 195:  reporting time step is less than routing time step.
              Self-explanatory.

ERROR 200:  one or more errors in input file.
              This message appears when one or more input file parsing errors (the 200-series
              errors) occur.

ERROR 201:  too many characters in input line.
              A line in the input file cannot exceed 1024 characters.

ERROR 203:  too few items at line n of input file.
              Not enough data items were supplied on a line of the input file.

ERROR 205:  invalid keyword at line n of input file.
              An unrecognized keyword was encountered when parsing a line of the input file.

ERROR 207:  duplicate ID name at line n of input file.
              An ID name used for an object was already assigned to an object of the  same
              category.

ERROR 209:  undefined object xxx at line n  of input file.
              A reference was made to an object that was never defined. An example would be
              if node 123  were  designated as the outlet point of a subcatchment, yet no such
              node was ever defined in the study area.

ERROR 211:  invalid number xxx at line n of input file.
              Either  a  non-numeric character was encountered where  a numerical value was
              expected or an invalid number (e.g., a negative value) was supplied.

ERROR 213:  invalid date/time xxx at line n of input  file.
              An invalid format for a date or time was encountered. Dates must be entered as
              month/day/year and times as either decimal hours or as hour:minute:second.
                                          280

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ERROR 217:   control rule clause out of sequence at line n of input file.
               Errors of this nature can occur when the format for writing control rules is not
               followed correctly (see Section C.3).

ERROR 219:   data provided for unidentified transect at line n of input file.
               A GR line with Station-Elevation data was  encountered in the  [TRANSECTS]
               section of the input file after an NC line but before any XI line that contains the
               transect's ID name.

ERROR 221:   transect station out of sequence at line n of input file.
               The station distances specified for the transect of an irregular cross section must
               be in increasing numerical order starting from the left bank.

ERROR 223:   Transect xxx has too few stations.
               A transect for an irregular cross  section must have at least 2 stations defined for
               it.

ERROR 225:   Transect xxx has too many stations.
               A transect cannot have more than 1500 stations defined for it.

ERROR 227:   Transect xxx has no Manning's N.
               No Manning's N was  specified for a transect (i.e., there was no  NC line in the
               [TRANSECTS] section of the input file.

ERROR 229:   Transect xxx has invalid overbank locations.
               The distance values specified  for either the left or right overbank locations of a
               transect do not match any of the distances listed for the transect's stations.

ERROR 231:   Transect xxx has no depth.
               All of the stations for a transect were  assigned the same elevation.

ERROR 233:   invalid treatment function expression at line n of input file.
               A treatment function supplied for a  pollutant at a specific node is either not a
               correctly  formed  mathematical expression or refers to  unknown  pollutants,
               process variables, or math functions.

ERROR 301:   files share same names.
               The input, report, and  binary output  files specified on the command line cannot
               have the same names.

ERROR 303:   cannot open input file.
               The input file either does not  exist or cannot be opened (e.g., it might be in use
               by another program).

ERROR 305:   cannot open report file.
               The report file cannot be opened (e.g., it might reside in a directory to which the
               user does not have write privileges).

ERROR 307:   cannot open binary results file.
               The binary output file cannot be opened (e.g., it might reside in a directory to
               which the user does not have write privileges).
                                           281

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ERROR 309:  error writing to binary results file.
               There was an error in trying to  write results to the binary output file (e.g., the
               disk might be full or the file size  exceeds the  limit imposed by the operating
               system).

ERROR 311:  error reading from binary results  file.
               The command line version of SWMM could not read results saved to the binary
               output file when writing results to the report file.

ERROR 313:  cannot open scratch rainfall interface file.
               SWMM could not open the temporary file it uses to collate data together from
               external rainfall files.

ERROR 315:  cannot open rainfall interface file xxx.
               SWMM could not open the specified rainfall interface file, possibly because it
               does not exist or because the user does not have write privileges to its directory.
ERROR 317:  cannot open rainfall data file xxx.
               An external rainfall data file could not be opened, most likely because it does not
               exist.

ERROR 319:  invalid format for rainfall interface file.
               SWMM was trying to read data from a designated rainfall interface file with the
               wrong format (i.e., it may  have been created for some other project or actually be
               some other type of file).

ERROR 321:  no data in rainfall interface file for gage xxx.
               This message occurs  when a project wants to  use a previously saved rainfall
               interface file, but cannot find any data for  one of its  rain gages in the interface
               file. It can also occur  if the gage uses data  from a user-prepared rainfall file and
               the station id entered for the gage cannot be found in the file.

ERROR 323:  cannot open runoff interface file xxx.
               A runoff interface file could not be  opened, possibly because it does not exist or
               because the user does not have write privileges to its directory.

ERROR 325:  incompatible data found in runoff interface file.
               SWMM was trying to read data from a designated runoff interface file with the
               wrong format (i.e., it may  have been created for some other project or actually be
               some other type of file).

ERROR 327:  attempting to read beyond end of runoff interface file.
               This error can occur when a previously saved runoff interface file is being used
               in a simulation with a  longer duration than the one that created the interface file.

ERROR 329:  error in reading from runoff interface file.
               A format error was encountered while trying to read data from a previously saved
               runoff interface file.
                                           282

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ERROR 331:  cannot open hotstart interface file xxx.
               A hotstart interface file could not be opened, possibly because it does not exist or
               because the user does not have write privileges to its directory.

ERROR 333:  incompatible data found in hotstart interface file.
               SWMM was trying to read data from a designated hotstart interface file with the
               wrong format (i.e., it may have been created for some other project or actually be
               some other type of file).

ERROR 335:  error in reading from  hotstart interface file.
               A format error was encountered while trying to read data from a previously saved
               hotstart interface file.

ERROR 336:  no climate file specified for evaporation and/or wind speed.
               This error occurs when  the user specifies that evaporation or wind speed data will
               be read from an external climate file, but no name is supplied for the file.

ERROR 337:  cannot open climate file xxx.
               An external climate data file could not be opened, most likely because it does not
               exist.

ERROR 338:  error in reading from  climate file xxx.
               SWMM was trying to  read data from an external  climate file with the wrong
               format.

ERROR 339:  attempt to read beyond end of climate file xxx.
               The specified external climate does not include data for the period of time being
               simulated.

ERROR 341:  cannot open scratch RDII interface file.
               SWMM could not open the temporary file it uses to store RDII flow data.

ERROR 343:  cannot open RDII interface file xxx.
               An RDII interface file could not be opened, possibly because it does not exist or
               because the user does not have write privileges to its directory.

ERROR 345:  invalid format for RDII interface file.
               SWMM was trying to read data  from a designated RDII interface file with the
               wrong format (i.e., it may have been created for some other project or actually be
               some other type of file).

ERROR 351:  cannot open routing interface file xxx.
               A routing interface file  could not  be opened, possibly because it does not exist or
               because the user does not have write privileges to its directory.

ERROR 353:  invalid format for routing  interface file xxx.
               SWMM was trying to read data from a designated routing interface file with the
               wrong format (i.e., it may have been created for some other project or actually be
               some other type of file).
                                           283

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ERROR 355:  mismatched names in routing interface file xxx.
              The names of pollutants found in a designated routing interface file do not match
              the names used in the current project.

ERROR 357:  inflows and outflows interface files have same name.
              In cases where a run uses one routing interface file to provide inflows for a set of
              locations and another to save outflow results, the two files cannot both have the
              same name.

ERROR 361:  could not open external file used for Time Series xxx.
              The external file used to  provide data for the named time series could not be
              opened, most likely because it does not exist.

ERROR 363:  invalid data in external file used for used for Time Series xxx.
              The external file used to provide data for the named time series has one or more
              lines with the wrong format.
WARNING 01: wet weather time step reduced to recording interval for Rain Gage xxx.
              The  wet weather time step was automatically reduced so that no period with
              rainfall would be skipped during a simulation.

WARNING 02: maximum depth increased for Node xxx.
              The maximum depth for the node was automatically increased to match the  top
              of the highest connecting conduit.

WARNING 03: negative offset ignored for Link xxx.
              The link's stipulated offset was below the connecting node's invert so its actual
              offset was set to 0.

WARNING 04: minimum elevation drop used for Conduit xxx.
              The  elevation drop  between the end nodes of the conduit was below 0.001 ft
              (0.00035 m) so the latter value was used instead to calculate its slope.

WARNING 05: minimum slope used for Conduit xxx.
              The  conduit's computed slope was below the user-specified Minimum Conduit
              Slope so the  latter value was used instead.

WARNING 06: dry weather time step increased to wet weather time step.
              The  user-specified time  step for computing  runoff during dry weather periods
              was lower than that  set for wet weather periods and was automatically increased
              to the wet weather value.

WARNING 07: routing time step reduced to wet weather time step.
              The  user-specified time step for flow routing was larger than the  wet weather
              runoff time step and was automatically reduced to the runoff time step to prevent
              loss of accuracy.
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WARNING 08: elevation drop exceeds length for Conduit xxx.
               The elevation drop across the ends of a conduit exceeds its length. The program
               computes the conduit's slope as the elevation drop divided by the length instead
               of using the more accurate right triangle  method. The user should check for
               errors in the length and in both the invert elevations and offsets  at the conduit's
               upstream and downstream nodes.

WARNING 09: time series interval greater than recording interval for Rain Gage xxx.
               The smallest time interval between entries in the precipitation time series used by
               the rain gage is greater than the recording time interval specified  for the gage. If
               this was not  actually intended then what appear to be continuous periods of
               rainfall in the time series will instead be read with time gaps in between them.
                                           285

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