A link represents the physical connection between two nodes and may be one of the following:
- A conduit, representing a closed pipe or an open channel.
- A control, representing a weir, pump or other ancillary flow control device, or in InfoWorks networks only, a blockage.
- A bridge (InfoWorks networks only)
- A channel (InfoWorks networks only)
- A river reach (InfoWorks networks only)
In the InfoWorks ICM network, each node must be connected by a link to at least one other node. A single node may have several links to other nodes.
A conduit that changes direction can be represented by two links, with a node at their junction.
For each link, one of the nodes must be specified as the 'upstream' end. This identifies the nominal direction of flow but is not necessarily the direction in which the water will always flow.
The upstream node – in combination with the invert level at the upstream end – is used by the system for allocating a unique label to the link.
The link's downstream node is given for information.