1D Objects

1D objects are used to schematise 1D networks. The way flow is calculated in these 1D networks is described in the section 1D Flow.

• Connection node

• 1D Boundary Condition

• 1D Lateral

• Manhole

• Pumpstation (without end node)

• Pumpstation (with end node)

• Weir

• Culvert

• Orifice

• Pipe

• Cross-section location

• Channel

1D Boundary Condition

Boundary condition for 1D connection nodes.

Geometry

Point

Attributes

Table 21 1D Boundary condition attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Connection node ID	connection_node_id	integer	Yes	-	ID of the connection node to place the 1D boundary condition on
Boundary type	boundary_type	integer	Yes	-	Sets the type to water level (1), velocity (2), discharge (3) or Sommerfeld (5). See Notes for modellers for details.
Time series	timeseries	text	Yes	[minutes since start of simulation],[m | m/s | m³/s]. See Notes for modellers for details.	Timeseries of water levels, flow velocities, discharges or water level gradients to be forced on the model boundary

Notes for modellers

General notes

• 1D boundary conditions can only be applied to connection nodes that have a single connection to the rest of the network.

• The pipe, channel, or structure directly connected to the boundary condition must have calculation type isolated.

• 1D boundary conditions cannot be placed on the same connection node as a pump station.

• 1D laterals placed on a connection node with a 1D boundary condition will be ignored.

• Surfaces and impervious surfaces mapped to a connection node with a 1D boundary condition will be ignored.

Time series

Format the time series as Comma Separated Values (CSV), with the time (in minutes since the start of the simulation) in the first column and the value (units dependent on the boundary type) in the second column. For example:

0,145.20
15,145.23
30,145.35
45,145.38
60,145.15

• The time series string cannot contain any spaces or empty rows

• The boundary condition time series is stored in the simulation template and is not part of the 3Di model itself. It can be overridden when starting a new simulation, without the need to create a new revision of the schematisation.

• The time unit in the 1D boundary condition table in the schematisation is minutes, while the 3Di API expects this input in seconds. A conversion is applied when the reading the data from the schematisation. If you upload a CSV file with 1D boundary condition time series via the simulation wizard, you can choose the time unit (see Boundary conditions)

• For boundary types velocity (2), discharge (3) and Sommerfeld (5), the drawing direction of the channel, pipe, or structure determines sign of the input value. For velocity and discharge, this means that if the 1D boundary condition is placed on the end connection node, positive values result in boundary outflow. For the Sommerfeld boundary, a positive gradient for a 1D boundary condition that is placed at the end connection node means that the waterlevel downstream is higher than upstream, i.e. this will result in boundary inflow.

• The time series must cover the entire simulation period.

• The time series values are interpolated between the defined times

• In case of multiple boundaries in 1 model: make sure they all have the same number of timeseries rows with the same temporal interval.

• When editing the time series field in using SQL (sqlite dialect), use char(10) as line separator. The example time series shown above would look like this:

  "0,145.20"||char(10)||"15,145.23"||char(10)||"30,145.35"||char(10)||"45,145.38"||char(10)||"60,145.15"
  

1D Lateral

Defines a lateral discharge (source or sink term) for the 1D domain

Geometry

Point

Attributes

Table 22 1D Lateral attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Connection node ID	connection_node_id	integer	Yes	-	ID of the connection node on which the 1D lateral should be placed
Time series	timeseries	text	Yes	[minutes since start of simulation],[m³/s]. See Notes for modellers for details.	Timeseries of lateral discharges to be added to the specified location

Notes for modellers

1D laterals placed on a connection node with a 1D boundary condition will be ignored.

Time series

Format the time series as Comma Separated Values (CSV), with the time (in minutes since the start of the simulation) in the first column and the value (m³/s) in the second column. For example:

0,0.2
15,10.0
30,20.0
45,7.5
60,0.0

• The time series string cannot contain any spaces or empty rows

• The lateral time series is stored in the simulation template and is not part of the 3Di model itself. It can be overridden when starting a new simulation, without the need to create a new revision of the schematisation.

• The time unit in the 1D lateral table in the schematisation is minutes, while the 3Di API expects this input in seconds. A conversion is applied when the reading the data from the schematisation. If you upload a CSV file with 1D lateral time series via the simulation wizard, the time units are seconds (see Laterals)

• Positive values represent a source (water is added to the node), negative values represent a sink (water is extracted from the node to the extent that this water is available in the node)

• The time series does not need to cover the entire simulation period.

• The time series values are interpolated between the defined times

• When editing the time series field in using SQL (sqlite dialect), use char(10) as line separator. The example time series shown above would look like this:

  "0,0.2"||char(10)||"15,10.0"||char(10)||"30,20.0"||char(10)||"45,7.5"||char(10)||"60,0.0"
  

Channel

A natural or artificial open channel. Channels can have a variable bed level, bed friction and cross section along their length. This information is stored in another object, the Cross-section location. A channel can have one or more cross-section locations, depending on the variability of the channel.

See Channels, culverts and pipes for more details.

Geometry

Linestring (two or more vertices)

Attributes

Table 23 Channel attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Calculation type	calculation_type	integer	Yes	-	Sets the 1D2D exchange type: embedded (100), isolated (101), connected (102), or double connected (105). See Calculation types.
Code	code	text	No	-	Name field, no constraints
Display name	display_name	text	No	-	Name field, no constraints
Distance between calculation points	dist_calc_points	decimal number	No	m	Maximum distance between calculation points, see Calculation point distance
End connection node ID	connection_node_end_id	integer	Yes	-	ID of end connection node
Start connection node ID	connection_node_start_id	integer	Yes	-	ID of start connection node
Zoom category	zoom_category	integer	No	-	Deprecated

When using the 3Di Schematisation Editor

• The Connection nodes and a Cross-section location are added automatically.

• Do not forget to fill in the required feature attributes for the Cross-section location.

Notes for modellers

• Use 1D channels wisely. In many applications, schematising waterways in 2D is preferable. See Channels, culverts and pipes and Calculation types.

• All channels must have at least one Cross-section location.

Calculation type ‘embedded’

• Embedded channels add extra connections between 2D grid cells, but ignore obstacles and levees.

• Make sure the embedded channel profile always lays partially below the DEM; embedded channels cannot ‘float’ above the DEM.

• Embedded channels only function when they connect several 2D grid cells, so make sure no embedded channel falls completely inside one 2D grid cell

• Do not place boundary conditions directly on embedded channels.

Calculation types ‘connected’ and ‘double connected’

For channels with calculation type ‘connected’ and ‘double connected’, 1D2D connections connect each 1D calculation point to the 2D cell it is in. Therefore, channels with these calculation types need to be in a 2D cell. Alternatively, you may use an Exchange line to customise the 1D2D connections. When using an exchange line, the channel does not need to be in 2D cells, but the exchange line needs to be in 2D cells.

Connection node

Location and ID of nodes to connect Channel, Culvert, Orifice, Weir, Pipe, Pumpstation (with end node), or Pumpstation (without end node) features. Manhole, 1D Lateral, and 1D Boundary Condition features are also defined at connection nodes. See Inflow objects for more information on how surfaces and impervious surfaces can be mapped to a connection node.

Geometry

Point

Attributes

Table 24 Connection node attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Initial water level	initial_waterlevel	decimal number	No	m above datum	Initial water level for the 1D domain
Code	code	text	No	-	Name field, no constraints
Storage area	storage_area	decimal number	No	m²	Adds additional storage capacity to a 1D network

Notes for modellers

Connection nodes and calculation nodes

Connection nodes are not the same as calculation nodes. When 3Di generates the computational grid from the schematisation, a calculation node is created for each connection nodes, but additional 1D calculation nodes may also be created in between. See the Grid section for further details.

Initial water level

• For calculation nodes that are added along the length of a channel, pipe, or culvert, initial water levels are linearly interpolated between connection nodes. See the Grid section for further details.

• The intial water level is stored in the simulation template and is not part of the 3Di model itself. It can be overridden when starting a new simulation, without the need to create a new revision of the schematisation.

Storage area

• Storage area on connection nodes is additional to the storage that is defined by the dimensions of channels, culverts and pipes. See Storage in the 1D domain for more details.

• To calculate storage volume from the storage area, the height of the water column (water level minus bottom level) needs to be known. If a manhole is defined at the connection node, the manhole’s bottom level is used. Otherwise, the lowest bottom (reference level or invert level) of the channels, culverts or pipes that connect to the connection node is used.

• For connection nodes that are not connected to channels, a storage area larger than zero is recommended.

• If a manhole is defined on the connection node, the storage area must be larger than zero. Note that the manhole dimensions (shape, width, and length) are for administrative purposes only and are not used to calculate the storage during the simulation.

• Connection nodes with large storage (i.e. the square root of the storage area is much larger than the width of the incoming channel) reduce the flow velocity and advective force.

Cross-section location

Object to define the dimensions, levels, and friction at a specified point along a Channel.

Geometry

Point

Attributes

Table 25 Cross-section location attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Bank level	bank_level	decimal number	Yes	m MSL	Exchange level for the 1D2D connections. Only used when calculation type is ‘connected’.
Code	code	text	No	-	Name field, no constraints
Cross-section height	cross_section_height	decimal number	see Cross-section shape	m	Height of the cross-section (only used for Closed rectangle cross-sections)
Cross-section shape	cross_section_shape	decimal number	Yes	-	Sets the cross-section shape, Cross-section shape
Cross-section table	cross_section_table	text	see Cross-section shape	m	CSV-style table of [height, width] or [Y, Z] pairs, see Cross-section shape
Cross-section width	cross_section_width	decimal number	see Cross-section shape	m	Width or diameter of the cross-section, see Cross-section shape
Friction type	friction_type	decimal number	Yes	-	See Friction type
Friction value	friction_value	decimal number	Yes	m1/2/s (Chèzy) or s/m1/3 (Manning)	Friction or roughness value
Reference level	reference_level	decimal number	Yes	m MSL	Lowest point of the cross-section

Notes for modellers

• A cross-section location should be placed on top of a channel vertex that is not the start or end vertex

• If the channel calculation point distance is smaller than the distance between cross section locations, values in the cross section locations along the channel are interpolated, see Calculation point distance.

• If there are multiple cross-section locations between two calculation nodes (not connection nodes), only the first cross-section location is used.

Reference level

This is the bed level of the channel and the reference level for the cross-section. For example, if the reference level is 12.0 m MSL and the cross-section a tabulated rectangle with a width of 5 m at height 0, this means that the channel is 5 m wide at 12.0 m MSL.

Cross-section shape

The following shapes are supported:

Table 26 Cross-section shapes

Shape	Value	Instructions
Closed rectangle	0	Specify cross-section height and cross-section width
Open rectangle	1	Specify cross-section width
Circle	2	Specify cross-section width (i.e., diameter)
Egg	3	Specify cross-section width. Height will be 1.5 * width.
Tabulated rectangle	5	Fill cross-section table as CSV-style table of height, width pairs
Tabulated trapezium	6	Fill cross-section table as CSV-style table of height, width pairs
YZ	7	Fill cross-section table as CSV-style table of Y, Z pairs
Inverted egg	8	Specify cross-section width. Height will be 1.5 * width.

Friction type

This attribute sets the friction type to:

• Chézy (1)

• Manning (2)

• Chézy with conveyance (3)

• Manning with conveyance (4)

Using the friction types with conveyance is advised for open Tabulated or YZ cross-sections, in case there is a significant variation of the water depths across the cross-section, for instance, in a scenario with overflowing floodplains.

Culvert

Culverts are used to schematise pipes in open water systems.

In contrast to an Orifice, the flow behaviour in a culvert is assumed to be determined by shape and much less dominated by entrance losses. Culverts can be used for longer sections of pipe-like structures and do not have to be straight. Shorter, straight culverts are best schematised as an Orifice.

Geometry

Linestring (two or more vertices)

Attributes

Table 27 Culvert attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Calculation type	calculation_type	integer	Yes	-	Sets the 1D2D exchange type: embedded (100), isolated (101), connected (102), or double connected (105). See Calculation types.
Code	code	text	No	-	Name field, no constraints
Cross-section height	cross_section_height	decimal number	see Cross-section shape	m	Height of the cross-section (only used for Closed rectangle cross-sections)
Cross-section shape	cross_section_shape	decimal number	Yes	integer	Sets the cross-section shape, Cross-section shape
Cross-section table	cross_section_table	text	see Cross-section shape	m	CSV-style table of [height, width] or [Y, Z] pairs, see Cross-section shape
Cross-section width	cross_section_width	decimal number	see Cross-section shape	integer	Width or diameter of the cross-section, see Cross-section shape
Display name	display_name	text	No	-	Name field, no constraints
Distance between calculation points	dist_calc_points	decimal number	No	m	Maximum distance between calculation points, see Calculation point distance
End connection node ID	connection_node_end_id	integer	Yes	-	ID of end connection node
End invert level	invert_level_end_point	decimal number	Yes	m MSL	Level of lowest point on the inside at the end of the culvert
Friction type	friction_type	decimal number	Yes	-	Sets the friction type to Chézy (1) or Manning (2)
Friction value	friction_value	decimal number	Yes	m1/2/s (Chèzy) or s/m1/3 (Manning)	Friction or roughness value
Start connection node ID	connection_node_start_id	integer	Yes	-	ID of start connection node
Start invert level	invert_level_start_point	decimal number	Yes	m MSL	Level of lowest point on the inside at the start of the pipe
Zoom category	zoom_category	integer	No	-	Deprecated

When using the 3Di Schematisation Editor

• The connection nodes are added automatically

Notes for modellers

The cross-section describes the inside of the culvert. If you only know the outer dimensions, you have to discount the wall thickness.

Discharge coefficients

The discharge is multiplied by this value. The energy loss caused by the change in flow velocity at the entrance and exit are accounted for by 3Di. The discharge coefficients can be used to account for any additional energy loss. ‘Positive’ applies to flow in the drawing direction of the structure (from start node to end node); ‘negative’ applies to flow in the opposite direction.

Manhole

Manholes are used to explicitly define the calculation type, bottom level, and/or 1D2D exchange level at the location of a connection node. In sewer models, they are commonly used to schematise inspection manholes, pumping station reservoirs and outlets. Manholes can also be used in open water systems, when you want to to explicitly set the calculation type, bottom level or 1D2D exchange level at a specific location.

Geometry

Point

Attributes

Table 28 Manhole attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Display name	display_name	text	No	-	Name field, no constraints
Bottom level	bottom_level	decimal number	Yes	m MSL	Manhole bottom level
Calculation type	calculation_type	integer	Yes	-	Sets the type of 1D2D exchange: embedded (0), isolated (1), or connected (2). See Calculation types.
Code	code	text	No	-	Name field, no constraints
Connection node ID	id	integer	Yes	-	ID of connection node on which manhole is placed
Drain level	drain_level	decimal number	No	m MSL	Exchange level for the 1D2D connection. See Notes for modellers.
Length	length	decimal number	No	m	Horizontal length of the manhole (not used in the calculation)
Manhole indicator	manhole_indicator	integer	Yes	m MSL	Defines the type of the manhole: inspection (0), outlet (1), or pumping station (2)
Shape	shape	text	No	-	Shape of the manhole in the horizontal plane (not used in the calculation): square (00), round (01), or rectangle (02)
Surface level	surface_level	decimal number	No	m MSL	Top of the manhole, e.g. street level (not used in the calculation).
Width	width	decimal number	No	m	Horizontal width of the manhole (not used in the calculation)
Zoom category	zoom_category	integer	No	-	Deprecated

Notes for modellers

• Connection nodes for which a manhole is defined, must have a storage area larger than zero.

• Only one manhole can be defined for each connection node.

Drain level

• Water can flow from the 1D domain to the 2D domain if the 1D water level exceeds the drain level (and vice versa).

• In 1D-2D models, this setting only applies to manholes with calculation type ‘connected’

• In 1D-only models, the drain level is used as the street level, above which the storage area widens to the “manhole storage area” value specified in the global settings.

• If the drain level is not filled in, 3Di will use the DEM value at the location of the manhole, or, in case of 1D-only models, the highest top of the pipes starting or ending at this manhole.

• In 1D-2D models, the 1D-2D exchange level is the maximum of the manhole drain level and the 2D cell’s bottom level. See the figures below for an illustration of this.

Drain level above lowest pixel in the 2D cell

Fig. 28 Manhole with a drain level below the 2D cell’s lowest pixel. The 1D2D exchange level that is used in the simulation equals the 2D cell’s bottom level.

Drain level below lowest pixel in the 2D cell

Fig. 29 Manhole with a drain level above the 2D cell’s lowest pixel. The 1D2D exchange level that is used in the simulation equals the manhole drain level.

Shape, width and length

These values describe the shape of the manhole in the horizontal plane (i.e. the manhole bottom). They are for administrative purposes only and do not affect the storage area of the connection node. These values are not used by 3Di.

Manhole indicator

This value is used for administrative and visualisation purposes only. It does not affect the calculation.

Surface level

This value is used for administrative purposes only. It does not affect the calculation

Pumpstation (without end node)

Pumpstation that pumps water out of the model domain. This can be used, for example, to simulate a final pumpstation that pumps the water to a sewage treatment plant that is outside of the model domain. See Pumps for details on how pumping stations work in 3Di.

If you want the pumpstation to pump the water to another location within the model, use Pumpstation (with end node)

Geometry

Point

Attributes

Table 29 Pumpstation (without end node) attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Capacity	capacity	decimal number	Yes	L/s	Pump capacity
Code	code	text	No	-	Name field, no constraints
Connection node ID	connection_node_id	integer	Yes	-	ID of connection node on which the pumpstation is placed
Display name	display_name	text	No	-	Name field, no constraints
Lower stop level	lower_stop_level	decimal number	Yes	m MSL	Pump switches off when the water level becomes lower than this level
Sewerage	sewerage	boolean	Yes	-	Indicates if the pumpstation is part of the sewerage system (True) or not (False)
Start level	start_level	decimal number	Yes	m MSL	Pump switches on when the water level exceeds this level
Type	type	integer	Yes	-	Sets whether pump reacts to water level at: suction side (1) or delivery side (2)
Upper stop level	upper_stop_level	decimal number	Yes	m MSL	Pump switches off when the water level exceeds this level
Zoom category	zoom_category	integer	No	-	Deprecated

Notes for modellers

• Multiple pumpstations may be defined for the same connection node. If their active ranges (start/stop level) overlap, they may pump at the same time.

Pumpstation (with end node)

Pumpstation that transports water from one connection node to another. See Pumps for details on how pumping stations work in 3Di. If you want the pumpstation to pump the water out of the model, use Pumpstation (without end node). You do not need to use a 1D boundary condition for this.

Geometry

Linestring (exactly two vertices)

Attributes

Table 30 Pumpstation (with end node) attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Capacity	capacity	decimal number	Yes	L/s	Pump capacity
Code	code	text	No	-	Name field, no constraints
Display name	display_name	text	No	-	Name field, no constraints
End connection node ID	connection_node_end_id	integer	Yes	-	ID of connection node to which the water is pumped
Lower stop level	lower_stop_level	decimal number	Yes	m MSL	Pump switches off when the water level becomes lower than this level
Sewerage	sewerage	boolean	Yes	-	Indicates if the pumpstation is part of the sewerage system (True) or not (False)
Start connection node ID	connection_node_start_id	integer	Yes	-	ID of connection node from which the water is pumped
Start level	start_level	decimal number	Yes	m MSL	Pump switches on when the water level exceeds this level
Type	type	integer	Yes	-	Sets whether pump reacts to water level at: suction side (1) or delivery side (2)
Upper stop level	upper_stop_level	decimal number	Yes	m MSL	Pump switches off when the water level exceeds this level
Zoom category	zoom_category	integer	No	-	Deprecated

Notes for modellers

• Multiple pumpstations may be defined for the same connection node. If their active ranges (start/stop level) overlap, they may pump at the same time.

Orifice

An orifice can be used to schematise hydraulic structures like gates, bridges, or culverts. It can be used in open water systems as well as in sewerage systems.

An orifice is commonly used to schematise structures that are closed at the top of the cross-section, whereas the Weir is commonly used for structures that are open at the top. However, both types of cross-sections can be used for either structure, and 3Di uses them in the calculation in the same way. See Weirs and Orifices for further details.

Geometry

Linestring (exactly two vertices)

Attributes

Table 31 Orifice attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Code	code	text	No	-	Name field, no constraints
Crest level	crest_level	decimal number	Yes	m MSL	Lowest point of the cross-section.
Crest type	crest_type	integer	Yes	-	Sets the crest type: broad-crested (3) or short-crested (4)
Cross-section height	cross_section_height	decimal number	see Cross-section shape	m	Height of the cross-section (only used for Closed rectangle cross-sections)
Cross-section shape	cross_section_shape	decimal number	Yes	-	Sets the cross-section shape, Cross-section shape
Cross-section table	cross_section_table	text	see Cross-section shape	m	CSV-style table of [height, width] or [Y, Z] pairs, see Cross-section shape
Cross-section width	cross_section_width	decimal number	see Cross-section shape	m	Width or diameter of the cross-section, see Cross-section shape
Discharge coefficient negative	discharge_coefficient_negative	decimal_number	Yes	-	Discharge in the negative direction is multiplied by this value
Discharge coefficient positive	discharge_coefficient_positive	decimal_number	Yes	-	Discharge in the positive direction is multiplied by this value
Display name	display_name	text	No	-	Name field, no constraints
End connection node ID	connection_node_end_id	integer	Yes	-	ID of connection node to which the water is pumped
Friction type	friction_type	decimal number	Yes	-	Sets the friction type to Chézy (1) or Manning (2)
Friction value	friction_value	decimal number	Yes	m1/2/s (Chèzy) or s/m1/3 (Manning)	Friction or roughness value
Sewerage	sewerage	boolean	Yes	-	Indicates if the structure is part of the sewerage system (True) or not (False)
Start connection node ID	connection_node_start_id	integer	Yes	-	ID of the start connection node
Zoom category	zoom_category	integer	No	-	Deprecated

When using the 3Di Schematisation Editor

• The connection nodes are added automatically

Notes for modellers

In the computational grid, an orifice will always be represented by a single flowline. Therefore, orifices do not have a calculation point distance and calculation type. The calculation type of the start and end nodes is determined by the channels, culverts, manholes, and pipes connected to them.

Crest level

This is the reference level for the cross-section. For example, if the crest level is 12.0 m and the cross-section a circle with a diameter of 0.5 m, the opening will start at 12.0 m and end at 12.5 m

Discharge coefficients

The discharge is multiplied by this value. The energy loss caused by the change in flow velocity at the entrance and exit are accounted for by 3Di. The discharge coefficients can be used to account for any additional energy loss. ‘Positive’ applies to flow in the drawing direction of the structure (from start node to end node); ‘negative’ applies to flow in the opposite direction.

Pipe

Pipe in a sewerage system.

Geometry

Linestring (exactly two vertices)

Attributes

Table 32 Pipe attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Calculation type	calculation_type	integer	Yes	-	Sets the 1D2D exchange type: embedded (0), isolated (1), or connected (2). See Calculation types.
Code	code	text	No	-	Name field, no constraints
Cross-section height	cross_section_height	decimal number	see Cross-section shape	m	Height of the cross-section (only used for Closed rectangle cross-sections)
Cross-section shape	cross_section_shape	decimal number	Yes	integer	Sets the cross-section shape, Cross-section shape
Cross-section table	cross_section_table	text	see Cross-section shape	m	CSV-style table of [height, width] or [Y, Z] pairs, see Cross-section shape
Cross-section width	cross_section_width	decimal number	see Cross-section shape	integer	Width or diameter of the cross-section, see Cross-section shape
Display name	display_name	text	No	-	Name field, no constraints
Distance between calculation points	dist_calc_points	decimal number	No	m	Maximum distance between calculation points, see Calculation point distance
End connection node ID	connection_node_end_id	integer	Yes	-	ID of end connection node
End invert level	invert_level_end_point	decimal number	Yes	m MSL	Level of lowest point on the inside at the end of the pipe
Friction type	friction_type	decimal number	Yes	-	Sets the friction type to Chézy (1) or Manning (2)
Friction value	friction_value	decimal number	Yes	m1/2/s (Chèzy) or s/m1/3 (Manning)	Friction or roughness value
Sewerage	sewerage	boolean	Yes	-	Indicates if the pumpstation is part of the sewerage system (True) or not (False)
Start connection node ID	connection_node_start_id	integer	Yes	-	ID of start connection node
Start invert level	invert_level_start_point	decimal number	Yes	m MSL	Level of lowest point on the inside at the start of the pipe
Material	material	integer	No	-	Pipe wall material, not used in the calculation. See Notes for modellers.
Sewerage type	sewerage_type	integer	Yes	-	Function of the pipe in the sewerage system. Used for visualisation and administrative purposes only. See Notes for modellers.
Zoom category	zoom_category	integer	No	-	Deprecated

When using the 3Di Schematisation Editor

• The connection nodes and manholes will be added automatically.

• To draw a single pipe, the geometry must have exactly 2 vertices. A line with more than 2 vertices will be split into several pipes.

• To digitize a trajectory of multiple pipes, first digitize the manholes, fill in the bottom levels, and then draw the pipe trajectory over these manholes by adding a vertex at each of the manholes. The pipes that are generated will use the manhole’s bottom levels as invert levels and the connection nodes and manholes will be added automatically.

Notes for modellers

The cross-section describes the inside of the pipe. If you only know the outer dimensions, you have to discount the wall thickness.

Adding a pipe trajectory

When you digitize (draw) a pipe feature with more than two vertices, each vertex will be converted into a connection node plus manhole, connected by pipes. If you digitize a pipe that connects existing manholes, the pipe(s) will use the manholes’ bottom levels as their invert levels and automatically refer to the correct the connection nodes. Therefore, the quickest way to digitize a trajectory of multiple pipes is to first digitize the manholes, fill in the bottom levels, and then draw the pipe trajectory over these manholes by adding a vertex at each of the manholes.

Material

The material is not used in the calculation, but can be used to estimate the friction value. The processing algorithm “Guess Indicators” recognizes the following values: 0: concrete; 1: pvc; 2: gres; 3: cast iron; 4: brickwork; 5: HPE; 6: HDPE; 7: plate iron; 8: steel.

Sewerage type

The following types are supported: - Combined sewer (0) - Storm drain (1) - Sanitary sewer (2) - Transport (3) - Spillway (4) - Syphon (5) - Storage (6) - Storage and settlement tank (7)

Weir

Overflow structure, used to control the water level. It can be used in open water systems as well as sewerage systems.

A weir is commonly used to schematise structures with open cross sections, whereas the Orifice is commonly used for structures that are closed at the top. However, both types of cross-sections can be used for either structure, and 3Di uses them in the calculation in the same way. See Weirs and Orifices for further details.

Geometry

Linestring (exactly two vertices)

Attributes

Table 33 Weir attributes

Attribute alias	Field name	Type	Mandatory	Units	Description
ID	id	integer	Yes	-	Unique identifier
Code	code	text	No	-	Name field, no constraints
Crest level	crest_level	decimal number	Yes	m MSL	Lowest point of the cross-section.
Crest type	crest_type	integer	Yes	-	Sets the crest type: broad-crested (3) or short-crested (4)
Cross-section height	cross_section_height	decimal number	see Cross-section shape	m	Height of the cross-section (only used for Closed rectangle cross-sections)
Cross-section shape	cross_section_shape	decimal number	Yes	-	Sets the cross-section shape, Cross-section shape
Cross-section table	cross_section_table	text	see Cross-section shape	m	CSV-style table of [height, width] or [Y, Z] pairs, see Cross-section shape
Cross-section width	cross_section_width	decimal number	see Cross-section shape	m	Width or diameter of the cross-section, see Cross-section shape
Discharge coefficient negative	discharge_coefficient_negative	decimal_number	Yes	-	Discharge in the negative direction is multiplied by this value
Discharge coefficient positive	discharge_coefficient_positive	decimal_number	Yes	-	Discharge in the positive direction is multiplied by this value
Display name	display_name	text	No	-	Name field, no constraints
End connection node ID	connection_node_end_id	integer	Yes	-	ID of connection node to which the water is pumped
Friction type	friction_type	decimal number	Yes	-	Sets the friction type to Chézy (1) or Manning (2)
Friction value	friction_value	decimal number	Yes	m1/2/s (Chèzy) or s/m1/3 (Manning)	Friction or roughness value
Sewerage	sewerage	boolean	Yes	-	Indicates if the structure is part of the sewerage system (True) or not (False)
Start connection node ID	connection_node_start_id	integer	Yes	-	ID of the start connection node
Zoom category	zoom_category	integer	No	-	Deprecated

Notes for the modeller

In the computational grid, a weir will always be represented by a single flowline. Therefore, weirs do not have a calculation point distance and calculation type. The calculation type of the start and end nodes is determined by the channels, culverts, manholes, and pipes connected to them.

Crest level

This is the reference level for the cross-section. For example, if the crest level is 12.0 m and the cross-section a circle with a diameter of 0.5 m, the opening will start at 12.0 m and end at 12.5 m

Discharge coefficients

The discharge is multiplied by this value. The energy loss caused by the change in flow velocity at the entrance and exit are accounted for by 3Di. The discharge coefficients can be used to account for any additional energy loss. ‘Positive’ applies to flow in the drawing direction of the structure (from start node to end node); ‘negative’ applies to flow in the opposite direction.