Page Comparison

...

1. Hover your mouse over the start node until you see a green target symbol.       
2. Left click and move your mouse to the end node for the link.

The first line you created will be the Primary drainage link. If you create another drainage line from the same node going to some other nodes, that will be created as Secondary drainage link.

Editing Drainage Link Properties describes the available drainage link properties in more detail, including the provision to specify flow-routing properties at each drainage link.

...