Weirs in InfoSWMM and SWMM5

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