Build-up/Washoff Land Use Data Fields

Build-up/Washoff Land Use data can be edited on the Build-up/Washoff Land Use Grid Window of the Subcatchments Grid or the Subcatchment 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 data, use the Property Sheet.

The following table describes all the data required to define a SWMM Build-up/Washoff Land Use model.

Common Data Fields

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

Build-up/Washoff Land Use Data

Database Table Name: hw_swmm_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 name or description that is used to identify this SWMM build-up /washoff land use. ID Text 64              
Sweep interval The number of days between street sweeping. sweep_interval Double   TD   0 0      
Sweep removal The fraction of pollutant buildup/washoff available for removal by street sweeping. The maximum is 1. sweep_removal Double       0 0 1    
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: hw_swmm_build_up

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
Determinant The name of the determinant can be selected from a list. determinant Text 6            

 
Build up type

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

  • NO_BUILDUP (none)
  • POWER_BUILDUP (Power)
  • EXPON_BUILDUP(Exponential)
  • SATUR_BUILDUP (Saturation)

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

 build_up_type Text 16              
Max. build-up The maximum possible buildup. max_build_up Double   SM   0 0      
Power rate constant The constant rate which is used by a POWER_BUILDUP (Power) build-up type. power_rate_constant Double   SB   0 0    

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

 
Exponential rate constant The constant rate which is used by a EXPON_BUILDUP(Exponential) build up type. exp_rate_constant Double   DR   0 0      
Half saturation constant The number of days to reach half of the maximum buildup, which is used by the SATUR_BUILDUP (Saturation) build-up type. saturation_constant Double   TD   0 0      
build_up Structure                
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: hw_swmm_washoff

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
Determinant The name of the determinant can be selected from a list. determinant Text 6              
Washoff type

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

  • NO_WASHOFF (none)
  • EXPON_WASHOFF(Exponential)
  • RATING_WASHOFF (Rating Curve)

  • EMC_WASHOFF (Event mean concentration)

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 EXPON_WASHOFF(Exponential) washoff type. exponential_washoff_coeff Double         0      
Rating washoff coefficient

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

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

 rating_washoff_coeff Double         0      
EMC washoff coefficient

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

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

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

Build-up/Washoff Land Use

Subcatchments Grid

Property Sheets