2D Boundary Data Fields (SWMM)

2D Boundary data can be edited on either the 2D Boundary Grid Window of the Lines Grid or the 2D Boundary 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 2D boundary data, use the Property Sheet.

The following describes all the data which can be used to define a 2D Boundary.

Common Data Fields

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

2D Boundary Data

Database Table Name: sw_2d_boundary_line

Field Name

Help Text

Database Field

Data Type

Size

Units

Precision

Default

Error Lower Limit

Error Upper Limit

Warning Lower Limit

Warning Upper Limit

Name

Name of the line

line_id

Text

Boundary line type

Database Value	Help Text
Vertical Wall	The boundary line is considered to be an impermeable infinitely high barrier. Water cannot flow out of, or into, the 2D Zone across the boundary line.
Critical Depth	At the boundary line, if the level in the boundary element of the 2D Zone is above the boundary face level, flow out of the 2D Zone will be calculated using a broad crested weir equation without energy loss. If the level in the boundary element is below the boundary face level, the boundary is considered to be a vertical impervious wall. Water cannot flow into the 2D Zone across the boundary line.
Supercritical	At the boundary line, if the flow in the boundary element is supercritical (Froude > 1) and directed outside of the 2D Zone, then the flow at the boundary face will be considered supercritical and calculated using the boundary element depth and velocity, regardless of the boundary face level. If the conditions of the flow are not supercritical, or the flow is going into the 2D Zone, the boundary face will be considered as a vertical wall. This situation is useful in areas where the user knows that the flow is flowing out of the 2D Zone without any effects on the 2D Zone. Water cannot flow into the 2D Zone across the boundary line.
Dry	The boundary line is considered to be bordered by a bottomless pit. Water that reaches the edge of the boundary line will flow out of the 2D Zone and will be lost from the simulation. Water cannot flow into the 2D Zone across the boundary line.
Normal Depth	It is assumed that slope balances friction forces (normal flow). Depth and velocity are kept constant when water reaches the boundary, so water can flow out without energy losses.
Inflow	Inflow / Outflow to the 2D Zone at the boundary line is defined by a profile in an Inflow event. The inflow is distributed evenly by length along the length of the boundary line.
Level	Depth of water at the boundary line is defined by a profile in a Level event. If the level of water in the boundary is below the boundary element ground level, the water depth at the boundary is considered zero. Therefore the boundary acts as a weir with crest level at the level of the boundary element.
Level & Head/discharge	Depth of water at the boundary line is defined by a profile in a Level event. If the level of water in the boundary is below the boundary element ground level, the water depth at the boundary is considered zero. The flow at the boundary is calculated from the head-discharge relationship specified in the Head unit flow table. The head is calculated as the depth at the boundary minus the depth at the element(s) attached to a 2D boundary line. Positive and negative heads beyond specification in the head unit flow table are calculated using linear extrapolation.

line_type

Text

Vertical Wall

Head unit flow table

Applicable when Boundary line type is set to Level & head/discharge.

The name of the Head Unit Flow table which is associated with this boundary line.

An existing Head unit flow table can be selected from the list or a new one can be added by selecting the button located to the left of this field.

head_unit_discharge_id

Text

Length

Length of the line.

length

Single

General Line XY Data

This field defines the coordinate of the line vertices. The underlying data consists of a series of (x,y) pairs. Each line is made up of a series of straight lines between the defined (x,y) pairs.

This data is not displayed on the grid or property sheet.

Coordinates of line vertices are included when you export line data to CSV files. There are two options available for exporting line coordinates. These are selected on the Select CSV Export Options Dialog using the Coordinate Arrays Format dropdown list. The options are:

Packed - The data is exported as a series of x,y pairs. {389904.,111350.,390309.,111765.}
Separately - the data is appended to the end of the row containing the line data. Each x and y value is in a separate (comma separated) field.

general_line_xy

Array

2D Boundaries

Head Unit Flow Data Fields (SWMM)

Lines

Lines Grid

Property Sheets

Show Columns	Database Names
	Size, Type and Units
	Defaults and Error Limits