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.
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
|
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
|
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
|
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:
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
|
|
|
|
|
|
|
|
|
