Inside SWMM5

Refactoring the SWMM 5 Help File – Projects in SWMM5

Projects in SWMM5

Project File

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 the SWMM 5.1 User’s 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 project1.inp then its settings file would have the name project1.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.

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 SWMM projects and how to set their default properties.

· Creating a new project
· Opening an existing project
· Saving a project
· Setting project defaults
· Units of measurement
· Registering calibration data
· Viewing all project data
Creating a New Project

To create a new project:

1. Select File >> New or click the button.
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 SWMM first begins.

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).
Opening an Existing Project

To open an existing project stored on disk:

1. Either select File >> Open or click the button.
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 that appears.
4. Click Open to open the selected file.

To open a project that was worked on recently:

1. Select File >> Reopen.
2. Select a file from the list of recently used files to open.
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:

· Default ID labels (labels used to identify nodes and links when they are first created)
· Default subcatchment properties (e.g., area, width, slope, etc.)
· Default node/link properties (e.g., node invert, conduit length, routing method).

To set default values for a project:

1. Select Project >> Defaults.
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.
Saving a Project

To save a project under its current name either select File >> Save or click the button.

To save a project using a different name, select File >> Save As. A standard Save File dialog will appear from which you can select the folder and name that the project should be saved under.

Project Defaults Dialog

The Project Defaults dialog is used to set default values for object properties and certain simulation options. The dialog has three tabbed pages covering the following categories:

· Default ID Labels
· Default Subcatchment Properties
· Default Node/Link Properties
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 will appear containing two tabbed pages – one for General Preferences and one for Numerical Precision.

Project Browser

The Project Browser appears when the Project tab on the left panel of SWMM’s Main Window is pressed. It provides access to all of the data in a project.

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 are used as follows:

adds a new object,

deletes the selected object,

edits the selected object,

moves the selected object up one position,

moves the selected object down one position,

sorts the objects in ascending order.

The vertical sizes of the list boxes in the browser can be adjusted by using the splitter bar located just below the upper box. The width of the Browser panel can be adjusted by using the splitter bar located along its right edge.

Selections made in the Project Browser are coordinated with objects highlighted on the Study Area Map, and vice versa. For example, selecting a conduit in the 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 Browser.

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:

1. Select the Options category from the Project Browser.
2. Select one of the following categories of options to edit:
· General Options
· Date Options
· Time Step Options
· Dynamic Wave Routing Options
· Interface File Options
· Reporting Options
· Event Options
3. Click the button to invoke the appropriate editor for the chosen option category (the Simulation Options dialog is used for the first 5 categories while the Reporting Options dialog and the Events editor are used for the last two, respectively).
Running a Simulation

After a study area has been suitably described, its runoff, 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 may occur.

· Setting simulation options
· Initiating a run
· Troubleshooting results
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 will appear containing two tabbed pages – one for General Preferences and one for Numerical Precision.

Saving a Project

To save a project under its current name either select File >> Save or click the button.

To save a project using a different name, select File >> Save As. A standard Save File dialog will appear from which you can select the folder and name that the project should be saved under.

Numerical Precision

The Numerical Precision page of the Preferencesdialog 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 variable, and then use the edit boxes next to them to select the number of decimal places to include when displaying computed results for the variable.

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.

Units of Measurement

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 automatically use those units. The units of previously entered data are not automatically adjusted if the unit system is changed.

US Standard Units
Area (Subcatchment) acres
Area (Storage Unit) square feet
Area (Ponding) square feet
Capillary Suction inches
Concentration milligrams / liter (mg/L)

micrograms / liter (ug/L)

counts / liter (#/L)

Decay Constant (Infiltration) 1 / hours
Decay Constant (Pollutants) 1 / days
Depression Storage inches
Depth feet
Diameter feet
Discharge Coefficient

Orifice

Weir

dimensionless

cubic feet / second /

feetn (CFS/ftn )

Elevation feet
Evaporation inches / day
Flow cubic feet /second (CFS)

gallons / minute (GPM)

million gallons / day (MGD)

Head feet
Hydraulic Conductivity inches / hour
Infiltration Rate inches / hour
Length feet
Manning’s n seconds / meter1/3
Pollutant Buildup mass / acre

mass / length

Rainfall Intensity inches / hour
Rainfall Volume inches
Slope (Subcatchments) percent
Slope (Cross Section) rise / run
Street Cleaning Interval days
Volume cubic feet
Width feet
SI Metric Units
Area (Subcatchment) hectares
Area (Storage Unit) square meters
Area (Ponding) square meters
Capillary Suction millimeters
Concentration milligrams / liter (mg/L)

micrograms / liter (ug/L)

Counts / liter (#/L)

Decay Constant (Infiltration) 1 / hours
Decay Constant (Pollutants) 1 / days
Depression Storage millimeters
Depth meters
Diameter meters
Discharge Coefficient

Orifice

Weir

dimensionless

cubic meters / second /

metern (CMS/metern )

Elevation meters
Evaporation millimeters / day
Flow cubic meters / second (CMS)

liters per second (LPS)

million liters / day (MLD)

Head meters
Hydraulic Conductivity millimeters / hour
Infiltration Rate millimeters / hour
Length meters
Manning’s n seconds / meter1/3
Pollutant Buildup mass / hectare

mass / length

Rainfall Intensity millimeters / hour
Rainfall Volume millimeters
Slope (Subcatchment) percent
Slope (Cross Section) rise / run
Street Cleaning Interval days
Volume cubic meters
Width meters

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