Flow Divider Nodes

Flow Dividers are drainage system nodes that divert inflows to a specific conduit in a prescribed manner. A flow divider can have no more than two conduit links on its discharge side. Flow dividers are only active under Kinematic Wave routing and are treated as simple junctions under Dynamic Wave routing.

There are four types of flow dividers, defined by the manner in which inflows are diverted:

• Cutoff Divider: Diverts all inflow above a defined cutoff value

• Overflow Divider: Diverts all inflow above the flow capacity of the non-diverted conduit

• Tabular Divider: Uses a table that expresses diverted flow as a function of total inflow

• Weir Divider: Uses a weir equation to compute diverted flow

The flow diverted through a weir divider is computed by the following equation:

$Q_{{div}} = C_w \left(f H_w\right)^{1.5}$

Where $Q_{{div}}$ is diverted flow, $C_w$ is Weir coefficient, $H_w$ is Weir height and $f$ is computed as:

$f = \frac{Q_{{in}} - Q_{{min}}}{Q_{{max}} - Q_{{min}}}$

Where $Q_{in}$ is the inflow to the divider, $Q_{min}$ is the flow at which diversion begins, and

$Q_{max} = C_w ({{H_w}})^{1.5}$

The user-specified parameters for the weir divider are $Q_{min}$, $H_w$, and $C_w$.

The principal input parameters for a flow divider are:

• Junction parameters (see above)

• Name of the link receiving the diverted flow

• Method used for computing the amount of diverted flow