Problem

When validating a model where a property connection element is connected to a diversion link the following user notification occurs;

“Tap node cannot reference a diversion link”

Background

This “red” user notification is generated when a property connection is connected to a conduit which is set as a diversion link via a tap node. The message would look like this;

A diversion link is used to define a flow split. The flow through the diversion link is based on the rating table of upstream flow vs. diverted flow.

When a property connection is applied to a diversion link (via tap and lateral) there is conflict which occurs due to the multiple flow conditions applied on the diversion link. A property connection would have sanitary loads to generate the flow to be assigned to a conduit which will determine the flow within the conduit. However, when this conduit is defined as diversion link, the flow within it is governed by the diversion rating curve.

As both these flow conditions are assigned to a same conduit (modeled as a diversion link) the user notification is generated to warn the user that calculation cannot be performed for this link. Also, since the conduit is defined as a diversion link the diversion rating curve will govern the flow.

Solution

To resolve this notification the following options can be adopted;

Option 1: Assign the Property Connection to the upstream node

This can be done by manually deleting the tap and lateral for the property connection and assigning the property connection to the upstream node. You can also right click on the end of the lateral link, choose "reconnect", and attach it to the manhole.

Option 2: Assign a transition

With this option you can simply divide the conduit by a transition element. After doing this, check the new downstream conduit and ensure that “False” is selected for the “Is Diversion Link?” property.

See Also

Modeling storm/sewer Property Connections

Modeling a flow split (diversion) with the SewerCAD or StormCAD numerical solver