Land Use Data Fields (SWMM)

Land Use data can be edited on either the Land Use Grid Window of the Subcatchments Grid or the Land Use Property Sheet.

Most data can be edited on the grid, but some fields cannot be displayed in the grid format.

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

This table describes all the data fields used to define a Land Use.

Common Data Fields

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

Land Use Data

Database Table Name: sw_land_use

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

Land use ID

The unique name that is used to identify this land use.

id

Text

254

 

0

 

 

 

 

 
Washoff

The rate at which pollutants are washed off during rain events. The rates are entered on a Washoff grid which is displayed by clicking on the button.

Database Table Name: sw_land_use_wo

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.

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

 pollutant Text 254              
Washoff type

The type of SWMM washoff function which is to apply to this pollutant can be selected from a list. The options are:

  • EXP (Exponential)
  • RC (Rating Curve)

  • EMC (Event mean concentration)

  • None

See the Build-up/Washoff Models topic for further information.

 washoff_type Text 16              
Exponential washoff coefficient The runoff coefficient (in (mm/h)-C2/h) used in the EXP (Exponential) washoff type. exponential_washoff_coeff Double         0      
Rating washoff coefficient

The runoff coefficient used in the RC (Rating Curve) washoff type.

This is specified in (m3/s)-C2mg/s or (m3/s)-C2/s, depending on the pollutant.

 rating_washoff_coeff Double         0      
EMC washoff coefficient

The event mean concentration runoff coefficient used in the EMC (Event mean concentration) washoff type.

This is specified in mg/m3 or 1/m3, depending on the pollutant.

 emc_washoff_coeff Double       0 0      
Washoff exponent The washoff exponent used in the EXP (Exponential) and RC (Rating Curve) washoff types. exponential_washoff_exponent Double       0 0      
Cleaning efficiency The street cleaning removal efficiency (percent) for the determinant. sweep_removal Double       0 0 100    
BMP removal efficiency Removal efficiency (percent) associated with any Best Management Practice (BMP) that may have been implemented. bmp_removal Double       0 0 100    
washoff Structure                
Build-up

The rate at which pollutants build up between rain events. The rates are entered on a Build-up grid which is displayed by clicking on the button.

Database Table Name: sw_land_use_bu

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.

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

 pollutant Text 254            

 
Build up type

The type of SWMM build up function which is to apply to this pollutant can be selected from a list. The options are:

  • POW (Power)
  • EXP (Exponential)
  • SAT (Saturation)
  • None

See the Build-up/Washoff Models topic for further information.

 build_up_type Text 4              
Max. build-up

The maximum possible build up.

max_build_up Double         0      
Power rate constant The constant rate which is used by a POW (Power) build up type. power_rate_constant Double   SB     0    

 
Power time exponent The time exponent which is used by a POW (Power) build up type. power_time_exponent Double         0    

 
Exponential rate constant The constant rate which is used by a EXP (Exponential) build up type. exp_rate_constant Double   DR     0      
Half saturation constant The number of days to reach half of the maximum buildup, which is used by the SAT (Saturation) build up type. saturation_constant Double   TD     0      
Unit

The type of unit which determines how build up is applied. The options are:

Area - Per unit area

Curb length - Per length of curb

 unit Text 16     Area        
build_up Structure                
Sweep interval The number of days between street sweeping. Street sweeping may reduce the amount of available built-up sediment during a simulation. sweep_interval Double   TD   0 0      
Sweep availability The fraction of pollutant buildup/washoff available for removal by street sweeping. The maximum is 1. sweep_removal Double   TD   0 0  

 

 
Last swept The number of days since the last sweep (surface removal of sediment) at the start of the event. last_sweep Double   TD   0 0  

 

 

Land Use

Subcatchments Grid

Pollutant Data Fields

Property Sheets