The program is able to model looped and branched channels. For routing reaches the direction of the flow must be from upstream to downstream. The reverse is not allowed.
Rules are required to define the split of flows at bifurcations and junctions. These are defined in the Abstraction which can be attached to the standard Junction or Reservoir.
A bifurcation, for example, has one inflow and two outflows. Two Abstractions are required at the downstream nodes to define the split of flows.
In general:
Qin = Qout
If a reservoir is to be modelled, abstractions must be attached to all the outflows.