Channel Data Fields

Channel data can be edited on either the Channel Grid Window of the Links Grid or the Channel Property Sheet.

To view and edit all channel data, use the Property Sheet.

This table describes all the river channel specific data which can be used to define a channel. For details of results fields, see the Link Results Data Fields topic.

Common Data Fields

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

Channel Data

Database Table Name: hw_channel

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

US node ID

Type in a node reference or choose an existing node reference from the drop down list. This makes up the first part of the link reference.

us_node_id

Text

DS node ID

Type in a node reference, or choose an existing node reference from the drop down list.

ds_node_id

Text

Link suffix

A single character between A and Z or 0 and 9 which completes the link reference. This allows a node to have up to 36 downstream links. The suffix is automatically allocated by the software.

link_suffix

Text

Link type

There are no additional options. The field is hidden on the grid, and read-only on the property sheet.

link_type

Text

Channl

Asset ID

For reference only. Designed as a reference to an asset database, but could be used for anything.

asset_id

Text

Sewer reference

An optional reference to identify the sewer of which this conduit is a part.

sewer_reference

Text

System type

Choose the system type from the dropdown list. See System Type for more information.

Database Value	Description	Help Text
STORM	Storm	Rainfall collection system
FOUL	Foul	Wastewater collection system (UK terminology)
SANITARY	Sanitary	Wastewater collection system (US terminology)
COMBINED	Combined	Rainfall and wastewater collection system
OVERLAND	Overland	Overland floodwater collection system
OTHER	Other	Other system type

system_type

Text

Other

Branch ID

Numeric field used to identify to which long section the link is associated.

Can be set manually or automatically (see Defining Branches topic for more information).

branch_id

Long Integer

US settlement efficiency (%)

The settlement efficiency fields allow you to set the effectiveness of an overflow for trapping out sediment. The overflow is a link (normally a pipe) attached to a node acting as a storage tank (storage node or manhole).

Normally the upstream end of the link will be attached to the node and act as the overflow.

The upstream settlement efficiency determines the efficiency for the overflow.

In some circumstances the link may be reversed (storage tank at the downstream end) and the downstream settlement efficiency will be used.

In many cases an overflow will attach to an outfall from the system.

It would be very unusual to have both upstream settlement efficiency and downstream settlement efficiency set to non-zero values.

The valid range is 0-100%. 0% means the overflow acts as a normal continuation link. 100% means that the overflow traps out as much sediment as possible.

us_settlement_eff

Long Integer

100

DS settlement efficiency (%)

See Upstream settlement efficiency.

ds_settlement_eff

Long Integer

100

Minimum computational nodes

The minimum number of computational nodes per link.

Default value is set in Simulation Parameters.

min_computational_nodes

Long Integer

99999999

Shape ID

Identifier of Channel Shape that defines the cross section of a barrel in the channel.

shape_id

Text

Base flow depth

This parameter allows you to override the base flow depth that InfoWorks ICM assigns to the river channel.

The default base flow depth for both a conduit and a river channel is the sediment depth + 5% (Base flow factor) of the conduit height minus the sediment depth. This is increased to 10% for conduits of slope greater than 0.01(Slope where base flow is doubled). This is subject to a minimum base flow depth of 0.02m (Minimum base flow depth). You can change these defaults for a particular network in the Simulation Parameters.

For a river channel, defining a base flow of 5% of the channel depth may have an excessive impact on hydraulic results, especially if your cross-section definition includes the flood plain. So you can set a user-defined value of base flow depth in each river channel.

Normally, a depth of a few centimetres should suffice. If your simulation results contain depth spikes, increasing the base flow depth may help.

If you set the user defined base flow depth to zero then InfoWorks ICM will calculate a base flow depth from the simulation parameters (see above). A non-zero base flow depth will be reset to the minimum base flow depth, if it is lower.

base_flow_depth

Double

5000

Sediment depth

You can define a depth of sediment in the invert of the river channel. This sediment reduces the capacity of the channel by obstructing the flow.

The maximum value for the sediment depth is 80% of channel height. This is the highest point defined in the channel shape profile.

The sediment depth represents permanent, consolidated sediment deposits. The system assumes that the sediment is constant; it does not allow for the erosion or deposition of sediment. The transport of sediment through the system is not modelled.

The default value for an individual channel is the global value specified in the User Defined Defaults (which has a default value of zero).

When running water quality simulations, the sediment transport calculations carried out by the water quality engine DO NOT feed values back to the hydraulic engine. The hydraulic calculations continue to use the fixed Sediment depth value

sediment_depth

Double

Number of barrels

The number of barrels, ie, identical parallel channels, that exist between the specified US node ID and DS node ID. Default is 1 (ie, a single channel).

number_of_barrels

Long Integer

100

Length

This is the length of the river channel. To preserve the stability of the model, lengths between 5m and 500m (16 and 1640 ft) are recommended.

length

Double

5000

Inflow

If the Inflow is lateral simulation parameter is checked, the simulation engine applies this inflow value laterally along the link.

If the Inflow is lateral parameter is not checked, the simulation engine applies this inflow value to the node at the end of the link with the highest invert level. In the case of equal invert levels, the flow is assigned to the upstream node.

There is a default figure for inflow in the user-defined defaults.

inflow

Double

Gradient

Calculated from upstream and downstream invert levels and link length.

Gradient is calculated automatically when carrying out Network Validation.

gradient

Double

Full capacity

The capacity of the link flowing just full.

Calculated automatically when carrying out Network Validation.

capacity

Double

US invert level

This is the invert level for the upstream end of the channel, measured above system datum. You must enter a value for this field.

There is no restriction on whether the upstream or downstream invert level is higher. However, the normal direction of flow would usually be defined as upstream to downstream.

us_invert

Double

-9999

9999

6000

DS invert level

see US invert level

ds_invert

Double

-9999

9000

6000

US headloss type

This defines the headloss conditions at the upstream end of the channel. InfoWorks ICM provides four built-in headloss curves, two of which can be used with river channels, or you can define your own headloss curves.

The two relevant built-in curves are:

None	no headloss
Fixed	the headloss coefficient represents the k value in the headloss equation. Unlike normal and high headloss types the k value remains the same regardless of surcharge ratio and flow direction

Select the curve you want from the dropdown list.

Fixed is the default, unless overridden by a user-defined default.

You can still choose the Normal and High built in curves from the list, but their use is not advised.

For more information on headloss, and how to define your own headloss curves, see Headloss Curves.

us_headloss_type

Text

DS headloss type

See US headloss type.

ds_headloss_type

Text

US headloss coefficient

This is a multiplying factor for the selected headloss curve to represent additional losses due mainly to channel bends.

The default is a value of 0, unless overridden by a user-defined default.

See Headloss Curves for more information.

us_headloss_coeff

Double

Base height

Height above invert of link.

Indicates where the nominal base is with regards to the use of the two (side and base) infiltration coefficients.

base_height

Double

0.0

Base infiltration loss coefficient

The rate of infiltration from the base of the river reach into the ground. Applicable between the invert and the Base height of the channel.

infiltration_coeff_base

Double

36000

Side infiltration loss coefficient

The rate of infiltration from the side of the river reach into the ground. Applicable above the Base height of the channel.

infiltration_coeff_side

Double

36000

DS headloss coefficient

See US headloss coefficient.

ds_headloss_coeff

Double

1D diffusion type

The type 1D diffusion can be set to River or Estuary. The default is Estuary unless overridden by a user-defined default.

Set to Estuary to calculate a diffusion coefficient that varies with tidal discharge and/or the longitudinal salinity gradient, or set to River to calculate a diffusion coefficient that is related to shear velocity.

Used for 1D diffusion water quality simulations only.

diff1_type

Text

User Defined Defaults

1D diffusion d0

If 1D diffusion type is set to Estuary, then d0 is a constant which is used to prevent unrealistically low values of dispersion from arising.

If 1D diffusion type is set to River, then d0 is the minimum diffusion coefficient.

The value of d0 must be ≥0 m2/s. The default is 0 m2/s unless overridden by a user-defined default.

Used for 1D diffusion water quality simulations only.

diff1_d0

Double

User Defined Defaults

1D diffusion d1

If 1D diffusion type is set to Estuary, then d1 is a constant which represents the amount of dispersion caused by tidal mixing in the estuary.

If 1D diffusion type is set to River, then d1 is the shear velocity factor.

The value of d1 must be ≥0 m2/s. The default is 0 m2/s unless overridden by a user-defined default.

Note

If the values d1 and d2 are zero, the diffusion coefficient is constant (the value of d0).

Used for 1D diffusion water quality simulations only.

diff1_d1

Double

User Defined Defaults

1D diffusion d2

This field is only enabled when 1D diffusion type is set to Estuary.

d2 is a constant which determines the effect of salinity gradient on dispersion. The value of d2 must be ≥0 m2/s. The default is 0 m2/s unless overridden by a user-defined default.

Note

If the value of d2 is non-zero then you should ensure that SAL (salt) is specified as a determinant in the QM parameters dialog. If the values d1 and d2 are zero the diffusion coefficient is constant (the value of d0).

Used for 1D diffusion water quality simulations only.

diff1_d2

Double

User Defined Defaults

Points

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

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

Link Vertice Export

Link vertices are included when you export link data to CSV files. There are two options available for exporting link vertices. 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.

Separately - the data is appended to the end of the row containing the link data. Each x and y value is in a separate (comma separated) field.

point_array

Array

Is merged

Check box to show if this link was created by merging other links together.

is_merged

Boolean

Channels

Links Grid

Property Sheets