I am wondering whether HEC-RAS can model a junction where the flow changes direction when modelling unsteady flow. Consider the following hypothetical scenario: two parallel channels connected mid way along their length by a perpendicular channel (in plan view the channels would form the letter H). Initially the flow in the perpendicular channel would be in 1 direction such that one junction would be a combining junction and one junction would be a dividing junction. Will HEC-RAS model the junctions correctly if the boundary conditions change over time such that the flow wants to reverse in the perpendicular channel? That is can a combining junction change on the fly to a dividing junction and vice versa?