The injection point of a lateral inflow into the hydraulic network can be modelled with a Lateral link connected to a Conduit or Channel via Tap node. A Tap is a node that references a Gravity Link and graphically displays the connection both in plan and profile view.

With the elevation and invert options available on both the upstream connected Lateral and the Tap itself, it is possible to display the vertical drop of a lateral connection. However the head loss through a plunging tributary surface or sub-surface flow is not simulated. Minor loss or junction loss through a tap connection cannot be modeled or computed.

A tap node can also be considered an internal hydraulic boundary in the model because the hydraulic conditions are not computed upstream of the tap. Within the GVF solvers, and similar to virtually-shaped sections, computational time is saved by not performing gradually varied flow analysis through the lateral links. Also, travel time is not accrued for a lateral rational flow until it reaches the boundary of the tap connection.

Taps cannot be placed on gutters, on pressure pipes or along lateral links. They can be attached at the downstream end of a lateral link. A tap may have several lateral links attached to it.

There is a Network Navigator query under Network Review for "Taps without Reference Link" to identify taps that aren't associated with a network hydraulic element.