Subject: Weirs in InfoSWMM
Figure 1 shows the relationship between the weir input data and the upstream and downstream nodes.
· Height,
· Crest and
· Node Invert Elevation
There are four types of weirs and if the weir becomes submerged downstream the Villemonte weir submergence correction is applied (Figure 2). You can have flow reversal across the weir unless you use a Flap Gate for the weir (Figure 3).
Figure 1: Definition of Weir Terms
Figure 2: Villemonte Weir Submergence Correction
Figure 3: Flow Reversal in a Weir