B.1 Rain Gage Properties

Property	Description
Name	User-assigned rain gage name.
X-Coordinate	Horizontal location of the rain gage on the Study Area Map. If left blank, the rain gage will not appear on the map.
Y-Coordinate	Vertical location of the rain gage on the Study Area Map. If left blank, the rain gage will not appear on the map.
Description	Click the ellipsis button (or press Enter) to edit an optional description of the rain gage.
Tag	Optional label used to categorize or classify the rain gage.
Rain Format	Format in which the rain data are supplied: - INTENSITY: Rainfall value is an average rate in inches/hour (or mm/hour) over the recording interval. - VOLUME: Rainfall value is the volume of rain that fell in the recording interval (in inches or millimeters). - CUMULATIVE: Rainfall value represents the cumulative rainfall since the start of the last series of non-zero values (in inches or millimeters).
Time Interval	Recording time interval between gage readings in either decimal hours or hours:minutes format.
Snow Catch Factor	Factor that corrects gage readings for snowfall.
Data Source	Source of rainfall data; either TIMESERIES for user-supplied time series data or FILE for an external data file.
TIME SERIES
- Series Name	Name of time series with rainfall data if Data Source selection was TIMESERIES; leave blank otherwise (double-click to edit the series).
DATA FILE
- File Name	Name of external file containing rainfall data (see Section 11.3).
- Station ID	Recording gage station identifier.
- Rain Units	Depth units (IN or MM) for rainfall values in user-prepared files (other standard file formats have fixed units depending on the format).

B.2 Subcatchment Properties

Property	Description
Name	User-assigned subcatchment name.
X-Coordinate	Horizontal location of the subcatchment's centroid on the Study Area Map. If left blank, the subcatchment will not appear on the map.
Y-Coordinate	Vertical location of the subcatchment's centroid on the Study Area Map. If left blank, the subcatchment will not appear on the map.
Description	Click the ellipsis button (or press Enter) to edit an optional description of the subcatchment.
Tag	Optional label used to categorize or classify the subcatchment.
Rain Gage	Name of the rain gage associated with the subcatchment.
Outlet	Name of the node or subcatchment which receives the subcatchment's runoff.
Area	Area of the subcatchment, including any LID controls (acres or hectares).
Width	Characteristic width of the overland flow path for sheet flow runoff (feet or meters).
% Slope	Average percent slope of the subcatchment.
% Imperv	Percent of land area (excluding the area used for LID controls) which is impervious.
N-Imperv	Manning's coefficient (n) for overland flow over the impervious portion of the subcatchment (see Section A.6 for typical values).
N-Perv	Manning's coefficient (n) for overland flow over the pervious portion of the subcatchment (see Section A.6 for typical values).
Dstore-Imperv	Depth of depression storage on the impervious portion of the subcatchment (inches or millimeters) (see Section A.5 for typical values).
Dstore-Perv	Depth of depression storage on the pervious portion of the subcatchment (inches or millimeters) (see Section A.5 for typical values).
% Zero-Imperv	Percent of the impervious area with no depression storage.
Subarea Routing	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.
Percent Routed	Percent of runoff routed between subareas.
Infiltration Data	Click the ellipsis button (or press Enter) to edit infiltration parameters for the subcatchment.
Groundwater	Click the ellipsis button (or press Enter) to edit groundwater flow parameters for the subcatchment.
Snow Pack	Name of snow pack parameter set (if any) assigned to the subcatchment.
LID Controls	Click the ellipsis button (or press Enter) to edit the use of low impact development controls in the subcatchment.
Land Uses	Click the ellipsis button (or press Enter) to assign land uses to the subcatchment. Only needed if pollutant buildup/washoff is modeled.
Initial Buildup	Click the ellipsis button (or press Enter) to specify initial quantities of pollutant buildup over the subcatchment.
Curb Length	Total length of curbs in the subcatchment (any length units). Used only when pollutant buildup is normalized to curb length.
N-Perv Pattern	Name of optional monthly pattern that adjusts pervious Manning’s n.
Dstore Pattern	Name of optional monthly pattern that adjusts depression storage.
Infil. Pattern	Name of optional monthly pattern that adjusts infiltration rate.

Note: 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 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.

B.3 Junction Properties

Property	Description
Name	User-assigned junction name.
X-Coordinate	Horizontal location of the junction on the Study Area Map. If left blank, the junction will not appear on the map.
Y-Coordinate	Vertical location of the junction on the Study Area Map. If left blank, the junction will not appear on the map.
Description	Click the ellipsis button (or press Enter) to edit an optional description of the junction.
Tag	Optional label used to categorize or classify the junction.
Inflows	Click the ellipsis button (or press Enter) to assign external direct, dry weather, or RDII inflows to the junction.
Treatment	Click the ellipsis button (or press Enter) to edit a set of treatment functions for pollutants entering the node.
Invert El.	Invert elevation of the junction (feet or meters).
Max. Depth	Maximum depth of the junction (i.e., from ground surface to invert) (feet or meters). If zero, the distance from the invert to the top of the highest connecting link will be used.
Initial Depth	Depth of water at the junction at the start of the simulation (feet or meters).
Surcharge Depth	Additional depth of water beyond the maximum depth that the junction can sustain before overflowing (feet or meters). This parameter can be used to simulate bolted manhole covers or force main connections.
Ponded Area	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.

B.4 Outfall Properties

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

B.5 Flow Divider Properties

Property	Description
Name	User-assigned divider name.
X-Coordinate	Horizontal location of the divider on the Study Area Map. If left blank, the divider will not appear on the map.
Y-Coordinate	Vertical location of the divider on the Study Area Map. If left blank, the divider will not appear on the map.
Description	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	Click the ellipsis button (or press Enter) to assign external direct, dry weather, or RDII inflows to the divider.
Treatment	Click the ellipsis button (or press Enter) to edit a set of treatment functions for pollutants entering the node.
Invert El.	Invert elevation of the divider (feet or meters).
Max. Depth	Maximum depth of the divider (feet or meters). See description for Junctions.
Initial Depth	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 the divider can sustain before overflowing (feet or meters).
Ponded Area	Area occupied by ponded water atop the junction after flooding occurs (sq. feet or sq. meters). See description for Junctions.
Diverted Link	Name of the link which receives the diverted flow.
Type	Type of flow divider: - 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

Property	Description
Cutoff Flow	Cutoff flow value used for a CUTOFF divider (flow units).

TABULAR Divider

Property	Description
Curve Name	Name of the Diversion Curve for a TABULAR divider (double-click to edit).

WEIR Divider

Property	Description
Min. Flow	Minimum flow at which diversion begins for a WEIR divider (flow units).
Max. Depth	Vertical height of the WEIR opening (feet or meters).
Coefficient	Product of the WEIR's discharge coefficient and its length. Typical values range from 2.65 to 3.10 per foot for flows in CFS.

Note: Flow dividers are operational only for Steady Flow and Kinematic Wave flow routing. For Dynamic Wave flow routing, they behave as Junction nodes.

B.6 Storage Unit Properties

Property	Description
Name	User-assigned storage unit name.
X-Coordinate	Horizontal location of the storage unit on the Study Area Map. If left blank, the storage unit will not appear on the map.
Y-Coordinate	Vertical location of the storage unit on the Study Area Map. If left blank, the storage unit will not appear on the map.
Description	Click the ellipsis button (or press Enter) to edit an optional description of the storage unit.
Tag	Optional label used to categorize or classify the storage unit.
Inflows	Click the ellipsis button (or press Enter) to assign external direct, dry weather, or RDII inflows to the storage unit.
Treatment	Click the ellipsis button (or press Enter) to edit a set of treatment functions for pollutants within the storage unit.
Invert El.	Elevation of the bottom of the storage unit (feet or meters).
Max. Depth	Maximum depth of the storage unit (feet or meters).
Initial Depth	Initial depth of water in the storage unit at the start of the simulation (feet or meters).
Surcharge Depth	Additional depth of water above full depth that a storage unit can sustain before overflowing (feet or meters). Only used for covered units.
Evap. Factor	Fraction of the potential evaporation from the storage unit’s water surface that is realized.
Seepage Loss	Click the ellipsis button (or press Enter) to specify optional soil properties that determine seepage loss through the bottom and sloped sides of the storage unit.
Storage Shape	Click the ellipsis button (or press Enter) to specify the shape of the storage unit by relating surface area to depth.

B.7 Conduit Properties

Property	Description
Name	User-assigned conduit name.
Inlet Node	Name of the node on the inlet end of the conduit (normally the end at higher elevation).
Outlet Node	Name of the node on the outlet end of the conduit (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	Maximum depth of the conduit’s cross-section (feet or meters).
Length	Conduit length (feet or meters).
Roughness	Manning’s roughness coefficient (n). See Section A.7 for closed conduit values or Section A.8 for open channel values.
Inlet Offset	Depth or elevation of the conduit invert above the node invert at the upstream end of the conduit (feet or meters).
Outlet Offset	Depth or elevation of the conduit invert above the node invert at the downstream end of the conduit (feet or meters).
Initial Flow	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 A.11.
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.
Seepage Loss Rate	Rate of seepage loss into surrounding soil (inches or millimeters per hour).
Flap Gate	YES if a flap gate exists that prevents backflow through the conduit, or NO if no flap gate exists.
Culvert Code	If the conduit is a culvert subject to possible inlet flow control, click the ellipsis button (or press Enter) to select a code number for its inlet geometry from those listed in Appendix A.10.
Inlets	Click the ellipsis button (or press Enter) to assign a storm drain inlet to a street or open channel conduit.

Note: Conduits and flow regulators (orifices, weirs, and outlets) can be offset some distance above the invert of their connecting end nodes. The choice of offset convention (Depth or Elevation) can be made on the Status Bar of SWMM’s main window or on the Node/Link Properties page of the Project Defaults dialog.

B.8 Pump Properties

Property	Description
Name	User-assigned pump name.
Inlet Node	Name of the node on the inlet side of the pump.
Outlet Node	Name of the node on the outlet side of the pump.
Description	Click the ellipsis button (or press Enter) to edit an optional description of the pump.
Tag	Optional label used to categorize or classify the pump.
Pump Curve	Name of the Pump Curve which contains the pump’s operating data (double-click to edit the curve). Enter * for an Ideal pump.
Initial Status	Status of the pump (ON or OFF) at the start of the simulation.
Startup Depth	Depth at the inlet node when the pump turns on (feet or meters). Enter 0 if not applicable.
Shutoff Depth	Depth at the inlet node when the pump shuts off (feet or meters). Must be lower than the Startup Depth. Enter 0 if not applicable.

…

B.9 Orifice Properties

Property	Description
Name	User-assigned orifice name.
Inlet Node	Name of the node on the inlet side of the orifice.
Outlet Node	Name of the node on the outlet side of the orifice.
Description	Click the ellipsis button (or press Enter) to edit an optional description of the orifice.
Tag	Optional label used to categorize or classify the orifice.
Type	Type of orifice (SIDE or BOTTOM).
Shape	Orifice shape (CIRCULAR or RECT_CLOSED).
Height	Height of the orifice opening when fully open (feet or meters). Corresponds to the diameter of a circular orifice or the height of a rectangular orifice.
Width	Width of a rectangular orifice when fully opened (feet or meters).
Inlet Offset	Depth or elevation of the bottom of the orifice above the invert of the inlet node (feet or meters).
Discharge Coeff.	Discharge coefficient (unitless). A typical value is 0.65.
Flap Gate	YES if the orifice has a flap gate that prevents backflow, NO otherwise.
Time to Open/Close	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.

B.10 Weir Properties

Property	Description
Name	User-assigned weir name.
Inlet Node	Name of the node on the inlet side of the weir.
Outlet Node	Name of the node on the outlet side of the weir.
Description	Click the ellipsis button (or press Enter) to edit an optional description of the weir.
Tag	Optional label used to categorize or classify the weir.
Type	Weir type: TRANSVERSE, SIDEFLOW, V-NOTCH, TRAPEZOIDAL, or ROADWAY.
Height	Vertical height of the weir opening (feet or meters).
Length	Horizontal length of the weir opening (feet or meters).
Side Slope	Slope (run/rise) of side walls for a V-NOTCH or TRAPEZOIDAL weir.
Inlet Offset	Depth or elevation of the bottom of the weir opening from the invert of the inlet node (feet or meters).
Discharge Coeff.	Discharge coefficient for flow through the central portion of the weir. 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 weirs.
Flap Gate	YES if the weir has a flap gate that prevents backflow, NO otherwise.
End Contractions	Number of end contractions for a TRANSVERSE or TRAPEZOIDAL weir whose length is shorter than the channel it is placed in. Values will be 0, 1, or 2 depending on the number of beveled ends.
End Coeff.	Discharge coefficient for flow through the triangular ends of a TRAPEZOIDAL weir.
Can Surcharge	YES if the weir can surcharge (have an upstream water level higher than the height of the opening), or NO if it cannot.
Coeff. Curve	Name of an optional Weir Curve that allows the central Discharge Coeff. to vary with head (ft or m) across the weir. Does not apply to Roadway weirs.

6.1 ROADWAY WEIR (Used Only for Roadway Weirs)

Property	Description
Road Width	Width of the roadway and shoulders (feet or meters).
Road Surface	Type of road surface: PAVED or GRAVEL.

B.17 Outlet Properties

Property	Description
Name	User-assigned outlet name.
Inlet Node	Name of the node on the inflow side of the outlet.
Outlet Node	Name of the node on the discharge side of the outlet.
Description	Click the ellipsis button (or press Enter) to edit an optional description of the outlet.
Tag	Optional label used to categorize or classify the outlet.
Inlet Offset	Depth or elevation of the outlet above the inlet node invert (feet or meters).
Flap Gate	YES if the outlet has a flap gate that prevents backflow, NO otherwise.
Rating Curve	Method of defining flow (Q) as a function of depth or head (y) across the outlet: - FUNCTIONAL/DEPTH: Uses a power function (Q = Ay^B) where y is the depth of water above the outlet’s opening at the inlet node. - FUNCTIONAL/HEAD: Uses the same power function except 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 the difference in head across the outlet’s nodes.

FUNCTIONAL (Used Only for a Functional Rating Curve)

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

TABULAR (Used Only for a Tabular Rating Curve)

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

B.18 Map Label Properties

Property	Description
Text	Text of the label.
X-Coordinate	Horizontal location of the upper-left corner of the label on the Study Area Map.
Y-Coordinate	Vertical location of the upper-left corner of the label on the Study Area Map.
Anchor Node	Name of the 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.
Font	Click the ellipsis button (or press Enter) to modify the font used to draw the label.

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