Roughness Definition Data Fields (SWMM)

Roughness definition data can be edited on either the Roughness Definition Grid Window of the Polygons Grid or the Roughness Zone 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 Roughness definition data, use the Property Sheet.

The following describes all the data which can be used to specify a Roughness definition.

Common Data Fields

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

Roughness Definition Data

Database Table Name: sw_roughness_definition

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

ID

The name of the Roughness definition.

definition_id

Text

64

 

0

 

 

 

 

 
Number of depth bands

The number of depth bands (roughness/depth thresholds) assigned to this definition can be selected from the dropdown list.

Option

Description

1

One roughness value can be specified (in the Roughness 1 (Manning's n) field) which will be applied to all mesh elements.

2

Two roughness values and one depth threshold value can be specified in the Roughness 1 (Manning's n), Depth threshold 1 and Roughness 2 (Manning's n) fields.

The roughness 1 value will be applied to mesh elements during the simulation until the depth threshold 1 value is reached. After this, the roughness 2 value will be applied to the mesh elements.
3

Three roughness values and two depth threshold values can be specified in the Roughness 1 (Manning's n), Depth threshold 1, Roughness 2 (Manning's n), Depth threshold 2, and Roughness 3 (Manning's n) fields.

The roughness 1 value will be applied to mesh elements during the simulation until the depth threshold 1 value is reached. After this, the roughness 2 value is used until the depth threshold 2 value is reached when the roughness 3 value will be applied to the mesh elements.
number_of_bands text 2   0          

Roughness 1 (Manning's n)

The value for Manning roughness (n) below the Depth threshold 1 if this is defined. Otherwise it represents the Manning roughness (n) applied for all depths.

roughness_1

Double

 

 

4

 

0

 

 

 
Depth threshold 1

The depth threshold at which the Roughness 2 (Manning's n) value is applied.

This field is only displayed when the Number of depth bands is set to 2 or 3.

See the description of Number of depth bands for further information.

 depth_thld_1     Y 3   0      

Roughness 2 (Manning's n)

The value for Manning roughness (n) above the Depth threshold 1 and below the Depth threshold 2 if this is defined.

This field is displayed when the Number of depth bands is set to 2 or 3.

See the description of Number of depth bands for further information.

roughness_2

Double

 

 

4

 

0

 

 

 
Depth threshold 2

The depth threshold at which the Roughness 3 (Manning's n) value is applied.

This field is displayed when the Number of depth bands is set to 3.

See the description of Number of depth bands for further information.

 depth_thld_2     Y 3   0      

Roughness 3 (Manning's n)

The value for Manning roughness (n) above the Depth threshold 2 if this is defined.

This field is only displayed when the Number of depth bands is set to 3.

See the description of Number of depth bands for further information.

roughness_3

Double

 

 

4

 

0

 

 

 

Roughness Definitions

Polygons

Polygons Grid

Property Sheets