The Crest overtopping tab allows a variation in the piezometric height in the upstream-downstream direction of the crest (see Figure 125). 

Figure 125

This change is evaluated as a percentage of the upstream overflow height. Only gravity dams and water intakes can consider overtopping. In addition, the user must define the segments that make up the crest profile (Gravity dam: Defining segments for the crest (optional), Intake: Segment definition for upstream opening, downstream opening and crest) so that the software can evaluate the submersion forces. These forces are included in upstream hydrostatic forces.