Performance of Submerged Ogee-Crest Weir Head-Discharge Relationships

Submergence is defined as the ratio of the tailwater to the headwater, both measured relative to the weir crest. The performance of published submerged ogee-crest head-discharge relationships was investigated in this study. Four submerged and one free-flow head-discharge relationship were evaluated relative to a submerged ogee-crest data set covering a range of tailwater elevations, discharges, and weir geometries. For submergence levels $<0.70$ , the head-discharge relationship was relatively independent of the tailwater elevation, but at higher submergence levels, this was not the case. For submergence values $<0.8$ , the submergence head-discharge data were best predicted using the free-flow head-discharge relationship. For submergence values $>0.8$ , the accuracies of all but one of the head-discharge relationships were very poor. For such high submergence levels, more accurate methods are needed for predicting submerged ogee-crest head-discharge relationships.