Node Data Fields (SWMM)

A SWMM network can include three different types of nodes; junction, outfall and storage.

Information relating to a node can be viewed and edited on the Node Grid Window of the Nodes Grid or on the Node Property Sheet, which contains all the properties related to a node.

To view and edit all node data, use the Property Sheet.

The table below describes all the data which can be used to define a Node. For details of results fields for nodes, see the Node Results Data Fields (SWMM) topic.

Common Data Fields

Fields that are common to the majority of objects can be found in the Common Fields topic.

Node Data

Database Table Name: sw_node

Show Columns

Database Names

Size, Type and Units

Defaults and Error Limits

Field Name

Help Text

Database Field

Data Type

Size

Units

Precision

Default

Error Lower Limit

Error Upper Limit

Warning Lower Limit

Warning Upper Limit
Node ID A unique name for the node, up to 254 letters, numbers and underscore characters. Upper and lower case letters are treated as being the same. node_id Text 254   0          
Node type

The type of node. The following options are available:

Database value

 Description
Junction A node in the network where links join together. Excess water at a junction can become partially pressurised while connecting conduits are surcharged and can either be lost from the system or be allowed to pond above the junction and subsequently drain back into the junction.
Outfall

A node in the network where flow leaves the node, normally by either discharging to a receptor, such as a receiving stream or treatment plant, with known water surface elevation, or by discharging to another subcatchment.
Storage A node in the network which represents a storage structure, such as a pond, which provides storage volume.

node_type

Text

10

 

0

 

 

 

 

 

x

The X co-ordinate for the node position.

x

Double

 

XY

1

 

 

 

 

 

y

The Y co-ordinate for the node position.

y

Double

 

XY

1

 

 

 

 

 
Invert elevation The elevation of the bottom of the node. invert_elevation Double   Z 3          
Ground level

Enabled when Node type is set to Junction or Storage.

The ground level of the node.

 ground_level Double   Z 3 0        
Max depth

Enabled when Node type is set to Junction or Storage.

The maximum depth of the node. This is normally equal to the value of the Ground level minus the Invert elevation and, if the default data flag (#D) is set, this will be automatically calculated when the Invert elevation and Ground level are specified.

 maximum_depth Double   Y 3 0        
Initial water depth

Enabled when Node type is set to Junction or Storage.

The initial depth of water in the node at the start of the simulation. This should not be greater than the specified Max depth.

 initial_depth Double   Y 3          
Surcharge depth

Enabled when Node type is set to Junction or Storage.

Additional depth of water beyond the maximum depth that is allowed before the junction or store floods.

 surcharge_depth Double   Y 3          
Ponded area

Enabled when Node type is set to Junction.

The area occupied by ponded water above the junction after flooding occurs.

 ponded_area Double   NA 3          

Flood type

Enabled when Node type is set to Junction.

Determines how flooding at a junction node will be handled during a 2D simulation.

The following options are available:

Database Value

 Description

Lost

Flood water is lost from the system.

2D

The discharge between surface storage (on the 2D mesh) and the junction is calculated using orifice equations, where the orifice width is taken as the circumference of the junction. See Defining 2D Nodes for further information.

flood_type

Text

8

 

0

 

 

 

 

 
Flooding discharge coefficient

Enabled when Flood type is set to 2D.

The discharge coefficient for the orifice flow equations used for calculating flooding at 2D nodes.

 flooding_discharge_coeff       2 0.5 0.01      
Treatment

A series of records which define a set of treatment functions for the removal of pollutants entering this particular node. The records are specified on a grid which is displayed by clicking on the button.

Database Table Name: sw_node_treat

Show Columns

Database Names

Size, Type and Units

Defaults and Error Limits

Field Name

Help Text

Database Field

Data Type

Size

Units

Precision

Default

Error Lower Limit

Error Upper Limit

Warning Lower Limit

Warning Upper Limit
Pollutant

The name of the pollutant that the treatment is to apply to.

Any pollutants already defined are included in the dropdown list.

 pollutant Text 254            

 
Result

The type of result can be set to either:

  • C - Effluent concentration
    For nodes of the type storage, this is the pollutant concentration within the node's stored volume; for all other types of nodes, this is the mixture concentration of all flow streams entering the node.

or

  • R - Fractional removal

Note that for each type of pollutant, a function for effluent concentration or fractional removal can be specified but not both.

 result Text 2              
Function

Determines the pollutant treatment at the node as a function of specified variables, such as flow rate, and water depth.

This takes the form of:

f(P, R_P, V)

Where:

P = is the name of one or more pollutants

R_P = one or more pollutant removals. Note that R_ must be prefixed to the name of the pollutant to indicate that it is to be removed.

V is one of the following variables:

  • Flow (flow rate into node)
  • Depth (water depth above node invert)
  • Area (node surface area)
  • DT (routing timestep)
  • HRT (hydraulic residence time)

Any of the standard operators +, -, *, /, ^ (for exponentiation) and any level of nested parentheses can be included in the function as well as any of the following mathematical functions:

  • abs(x) - the absolute value of x
  • sgn(x) - either +1 (for x >= 0) or -1 otherwise
  • step(x) - either 0 (for x <= 0) or 1 otherwise
  • sqrt(x) - the square root of x
  • log(x) - the logarithm base e of x
  • log10(x) - the logarithm base 10 of x
  • exp(x) - e raised to the x power
  • any standard trig functions (sin, cos, tan, and cot)
  • any inverse trig functions (asin, acos, atan, and acot)
  • any hyperbolic trig functions (sinh, cosh, tanh, and coth)

Closed

function Memo                
treatment Structure                
Sewershed contributing area

The area of the sewershed that contributes rainfall-dependent infiltration/inflow to the node.

This is typically only a small, localised part of the subcatchment area that contributes surface runoff to the node.

 unit_hydrograph_area Double   A 3 0 0      
Unit hydrograph

The unit hydrograph group associated with this node.

Any group already defined can be selected from the dropdown list. Alternatively, a new one can be added or an existing one modified using the button located to the left of the field. This displays the non-visual object menu, from which you can select the appropriate option.

The unit hydrographs in the group are used with the group's associated rain gage to develop a time series of RDII inflows per unit area over the period of the simulation.

 unit_hydrograph_id Text 254              
Baseline inflow A constant baseline value applied to the hydrographs associated with this node. inflow_baseline Double   Q 3 0        
Inflow scale factor

The scale factor which adjusts the values of the direct inflow time series.

A scale factor can be used, for example, to change the magnitude of an inflow hydrograph while keeping its shape the same, without having to re-edit the entries in the hydrograph time series, or to allow a group of nodes sharing the same time series to have their inflows behave in a time-synchronised fashion while allowing their individual magnitudes be different.

Note that the Baseline inflow value is not adjusted by this factor.

inflow_scaling

 Double     3 1        
Inflow pattern The name of a time pattern which can be used to adjust the Baseline inflow on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified).

inflow_pattern

 Text 254   0          
Pollutant inflow

This field contains a series of records defining the inflow of pollutants to this node. These are entered on a grid which is displayed by clicking on the button.

Database Table Name: sw_node_pol_inflow

Field Name

Help Text

Database Field

Data Type

Size

Units

Precision

Default

Error Lower Limit

Error Upper Limit

Warning Lower Limit

Warning Upper Limit
Pollutant

The name of a new inflow pollutant can be typed in or an existing one can be selected from a list of defined pollutants.

pollutant Text 254              
Baseline The value of the constant baseline component of the pollutant's inflow. baseline Double     3 0        
Baseline pattern The name of a time pattern whose factors adjust the Baseline on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). baseline_pattern Text                
Scaling

The scale factor which adjusts the values of the pollutant's inflow time series.

A scale factor can be used, for example, to change the magnitude of an inflow hydrograph while keeping its shape the same, without having to re-edit the entries in the hydrograph time series, or to allow a group of nodes sharing the same time series to have their inflows behave in a time-synchronised fashion while allowing their individual magnitudes be different.

Note that the Baseline value is not adjusted by this factor.

 scaling Double     3 1        
Mass units factor

A factor for converting pollutant inflow values into mass units.

This factor is only required for a mass type of pollutant and not for a pollutant concentration.

 mass_unit_factor Double     3 1        
pollutant_inflows Structure                
Base flow The average baseline value for the dry weather flow (DWF) and any corresponding constituents entering this node. base_flow Double   Q 3 0        
Base flow pattern 1 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_1 Text 254              
Base flow pattern 2 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_1 Text 245              
Base flow pattern 3 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_1 Text 254              
Base flow pattern 4 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_1 Text 254              
Pollutant DWF

This field contains a series of records defining the dry weather flow of pollutants to this node. These are entered on a grid which is displayed by clicking on the button.

Database Table Name: sw_node_pollutant_dwf

Field Name

Help Text

Database Field

Data Type

Size

Units

Precision

Default

Error Lower Limit

Error Upper Limit

Warning Lower Limit

Warning Upper Limit
Pollutant

The name of a new dry weather flow pollutant can be typed in or an existing one can be selected from a list of defined pollutants.

pollutant Text 254              
Baseline The value of the constant baseline component of the pollutant's inflow. baseline Double     3 0        
Base flow pattern 1 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_1 Text 254              
Base flow pattern 2 The time pattern of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_2 Text 254              
Base flow pattern 3 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_3 Text 254              
Base flow pattern 4 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_4 Text 254              
pollutant_dwf                  
Additional DWF

This field contains a series of records defining the dry weather flow of additional inflows to this node. These are entered on a grid which is displayed by clicking on the button.

Database Table Name: sw_node_additional_dwf

Field Name

Help Text

Database Field

Data Type

Size

Units

Precision

Default

Error Lower Limit

Error Upper Limit

Warning Lower Limit

Warning Upper Limit
Baseline The value of the constant baseline component of the additional inflow. baseline Double   Q 3 0        
Base flow pattern 1 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_1 Text 254              
Base flow pattern 2 The time pattern of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_2 Text 254              
Base flow pattern 3 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_3 Text 254              
Base flow pattern 4 The name of a time pattern which can be used to adjust the Base flow. This may be on either an hourly, daily, weekend hourly or monthly basis (depending on the type of time pattern specified). bf_pattern_4 Text 254              
additional_dwf                  
Outfall type

Displayed only when Node type is set to Outfall.

Specifies how outfall (flow) leaves the node. The following options are available:

Database value

 Description
Free Outfall is determined by the minimum of critical flow depth and normal flow depth in the connecting conduit.
Normal Outfall is based on the normal flow depth in the connecting conduit.
Fixed Outfall set to a fixed value.
Tidal Outfall is in accordance with a tidal curve.
Timeseries Outfall is accordance with a level event.

 

 outfall_type Text 10              
Tide gate

Displayed only when Node type is set to Outfall, and enabled when Outfall type is set to Free or Normal.

A check box which indicates whether or not a tide gate, which prevent blackflow through the node, is present. Unchecked (no tide gate) by default.

 flap_gate Boolean       False        
Fixed stage

Displayed only when Node type is set to Outfall and Outfall type is set to Fixed.

The elevation at which flow leaves the node.

 fixed_stage Double   Z 3          
Route to subcatchment

Displayed only when Node type is set to Outfall.

The name of the subcatchment that receives the outfall.

 route_subcatchment Text 254              
Tidal curve

Displayed only when Node type is set to Outfall, and Outfall type is set to Tidal.

The name of the tidal curve which supplies the outfall data.

Any curve already defined can be selected from the dropdown list. Alternatively, a new one can be added or an existing one modified using the button located to the left of the field. This displays the non-visual object menu, from which you can select the appropriate option.

 tidal_curve_id Text 254              
Storage type

Displayed only when Node type is set to Storage.

Specifies how the surface area of the storage node varies with water depth. The following options are available:

Database value

 Description
Functional

Uses the following function to calculate how the surface area varies with depth:

Area = A×(Depth)B + C

Tabular Uses a storage curve to determine the how the surface area varies with depth.
storage_type Text 10              
Storage curve

Displayed only when Node type is set to Storage, and Storage type is set to Tabular.

Name of the storage curve which provides the surface area and depth for this storage node.

Any group already defined can be selected from the dropdown list. Alternatively, a new one can be added or an existing one modified using the button located to the left of the field. This displays the non-visual object menu, from which you can select the appropriate option.

The curve will be extrapolated to meet the Max depth if required.

 storage_curve Text 254              
Coeff of shape function

Displayed only when Node type is set to Storage, and Storage type is set to Functional.

The value of the coefficient (A) in the storage type functional equation.

 functional_coefficient Double     3          
Constant of shape function

Displayed only when Node type is set to Storage, and Storage type is set to Functional.

The value of the constant (C) in the storage type functional equation.

 functional_constant Double     3          
Exponent of shape function

Displayed only when Node type is set to Storage, and Storage type is set to Functional.

The value of the exponent (B) in the storage type functional equation.

 functional_exponent Double     3          
Evaporation factor

Displayed only when Node type is set to Storage.

The fraction of the potential evaporation from the storage node's water surface that is actually realised.

 evaporation_factor Double     3          
Hydraulic conductivity

Displayed only when Node type is set to Storage.

Soil saturated hydraulic conductivity.

 conductivity Double     3    

 

 

 
Initial moisture deficit

Displayed only when Node type is set to Storage.

The soil (initial) moisture deficit is the fraction difference between the soil porosity and actual moisture content, expressed as a percentage. The Green-Ampt topic contains typical values used for different soil types.

 initial_moisture_deficit Double MOIST_DEF   3    

 

 

 
Capillary suction

Displayed only when Node type is set to Storage.

This is the average capillary suction at the wetting front. It depends on the soil type. The Green-Ampt topic contains typical values used for different soil types.

 suction_head Double   ID 3          

Nodes

Property Sheets

Nodes Grid